Kessler, R.C., Stang, P., Wittchen, H.U., Stein, M. & Walters, E.E. (1999). .... other anxiety and mood disorders (Chartier, Walker & Stein, 2003; Kessler, Stang,.
Epidemiology and Psychological Treatment of Social Phobia
Zeynep Ceren Acartürk
Doctoral Committee:
Prof. dr. A. van Balkom Prof. dr. M. van der Gaag Prof. dr. B. Penninx Prof. dr. J. Spijker Prof. dr. Ph. Spinhoven Prof. dr. J. Swinkels
This thesis was prepared at the Department of Clinical Psychology of the Vrije Universiteit in Amsterdam in close cooperation with the Trimbos Institute, which is the Netherlands Institute of Mental Health and Addiction in Utrecht.
Financial support for the printing of this thesis has been kindly provided by F.A. Acartürk. Cover design: Seda Welsh Printed by: Ipskamp Drukkers B.V., Amsterdam, NL &RS\ULJKW =&HUHQ$FDUWUNøVWDQEXODQGAmsterdam. All rights reserved. No parts of this book may be produced, in any form, without prior written permission of the author.
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VRIJE UNIVERSITEIT
Epidemiology and Treatment of Social Phobia
ACADEMISCH PROEFSCHRIFT ter verkrijging van de graad Doctor aan de Vrije Universiteit Amsterdam, op gezag van de rector magnificus prof.dr. L.M. Bouter, in het openbaar te verdedigen ten overstaan van de promotiecommissie van de faculteit der Psychologie en Pedagogiek op donderdag 28 mei 2009 om 10.45 uur in de aula van de universiteit, De Boelelaan 1105
door Zeynep Ceren Acartürk geboren te Istanbul, Turkije
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promotor: copromotoren:
prof.dr. W.J.M.J. Cuijpers dr. A. van Straten dr.ir. R. De Graaf
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To my mother and father
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CONTENTS Chapter 1
Introduction
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Chapter 2
Social Phobia and number of social fears, and their association
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with comorbidity, health-related quality of life and help seeking: A population-based study Chapter 3
Economic costs of social phobia: a population-based study
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Chapter 4
Incidence of social phobia and identification of its risk indicators: A 63 Model for Prevention
Chapter 5
Psychological Treatment of Social Anxiety Disorder: A Meta-
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Analysis Chapter 6
General Discussion
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English summary
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Dutch summary
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Acknowledgement
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Chapter 1 Introduction
“He dare not come in company, for fear he should be misused, disgraced, overshoot himself in gestures of speeches...He thinks every man observed him…” Hippocrates (unknown date) Preface Human beings are social animals. This implies that most of them want to be a member of social groups and to be accepted and valued by others of their group. Whether or not a person is accepted by a group, depends on the members of the group and is not fully under control by the individual. The uncertainty whether one is accepted or not, causes some form of social anxiety at any time in most individuals. Despite this social anxiety, however, most people are comfortable in most social situations, whereas some others are not. To a certain extent, social anxiety is normal and can be considered to be a part of human life. But in some cases this social anxiety is excessively high and is not related to the social situations this person is in. But where does social anxiety stop being “normal” and where does it start to become pathological? And what can be done to prevent the onset of social phobia and to treat existing social phobia?
These are the questions at which this thesis will focus, and it will try to contribute to a further understanding of the epidemiology, the burden of disease of social phobia, the incidence, economic costs and effective treatments. In the following sections I will first describe the key concepts related to social phobia and then I will present the structure of this thesis.
1. Diagnosis of Social Phobia Although the category of anxiety disorders was included in the first edition of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-I, 1952) (Murphy & Leighton, 2008), it took years to accept social phobia as a unique diagnose. A decade after Marks (1970) categorized the phobic disorders, social phobia became an official diagnose at DSM-III (APA, 1980). According to the current version of the DSM-IVTR (APA, 2000) social phobia is characterized by a persistent fear of negative evaluation or
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scrutiny by others in social or performance situations. Exposure to the feared social situation almost always leads to anxiety or to a panic attack. During these panic attacks the person experiences a number of somatic symptoms such as blushing, heart palpitations, tense muscles, and sweating. To be diagnosed as social phobia the following additional criteria need to be fulfilled: the person must realize that the fear is excessive, the person either avoids the feared situations or feel high levels of anxiety when exposed to it, and the fear must interfere significantly with the functions of the person in various domains of her or his life. All the symptoms have to be present for at least six months.
Following the inclusion of social phobia as a diagnosis in the DSM, an effort was made by researchers to investigate the unique character and possible subtypes of social phobia (Heimberg, Hope, Dodge & Becker, 1990). As a result of those studies, two types of social phobia have been distinguished. One is called “generalized social phobia” and the other “discrete”, “specific” or “nongeneralized phobia” (Heimberg, Holt, Schneier, Spitzer, & Liebowitz, 1993). Generalized social phobia is characterized by fear for all or almost all social situations while nongeneralized phobia is limited to one or a few situations of which the most common is speaking in front of other people (Schneier et al., 1992; Stein & Chavira, 1998).
However, this classification induced a debate which continues until today. A number of epidemiological and clinical studies have found some evidence for the existence of a generalized social phobia subtype but others have raised considerable criticism against this subtyping, especially because the meaning of “most social situations” remains unclear (Furmark et al., 2000; Vriends et al., 2006). Some researchers consider “most social situations” as a “larger” number of social situations, which implies that this is a quantitive distinction (Heimberg et al., 1993). Others, however, see it as a qualitative distinction (Turner et al., 1992) and label social fears related to the interactions with others as generalized social phobia. In the DSM-IV-TR, the subtypes of social phobia are not recognized as separate disorders. However, within the main diagnoses of social phobia there is an option to diagnose it as generalized phobia.
Although full-blown social phobia is defined explicitly, the definition of subthreshold social phobia is not stated in diagnostic handbooks. However, some previous studies have tried to define it (Davidson et al., 1994; Wittchen et al., 2000). Subthreshold social phobia has been 8
defined in most studies as having one or more symptoms of social phobia but without experiencing significant functional impairment as stated in the E criterion of DSM-IV-TR (reference). Earlier studies have found evidence that persons with subthreshold social phobia have significantly decreased quality of life and increased functional impairments compared to persons with no social phobia (Davidson et al., 1994; Wittchen et al., 2000).
2. Etiology 2.1. Cognitive-Behavioral Model of Social Phobia
After social phobia was defined as a distinct type of phobia (Marks, 1970), many theories such as neurobiological, behavioral, or cognitive behavioral tried to explain the origins of it. Although there are other models in clinical psychology, the cognitive behavioral model of social phobia is undoubtedly the most important model. The success of cognitive behavioral therapies in the treatment of social phobia has certainly resulted in a stronger focus of researchers on this theoretical model.
In the cognitive behavioral model of social phobia by Rapee and Heimberg (1997), it is assumed that social phobia lies on a continuum from a low (shyness) to an extreme (avoidant personality disorder) degree of concern about social evaluation. According to this model, people with social phobia believe that other people are extremely critical and being appraised positively by others is considered to be very important. When a person with social phobia enters a social situation, he (or she) forms a mental representation of himself as seen by the “audience” (anybody in the social environment with which there is a possibility for social interaction). With this internal representation of the self in mind, the person is waiting for external indicators of any perceived threat in the social environment.
The mental representation of the self is based on input from long-term memory (e.g. prior experiences), internal cues (e.g. physical symptoms), and external cues (e.g. feedback from audience). Then, the person rapidly compares the mental representation of the self as seen by the audience, with the appraisal of audience’s expected standard. The discrepancy between these two determines the probability of negative evaluation from the audience and its possible consequences. When the person predicts negative evaluation, anxiety starts with its physiological (e.g. blushing), cognitive (e.g. negative thoughts about self), and behavioral (e.g. avoidance) symptoms. Subsequently, these perceived internal cues will influence the 9
person’s mental representation of self as seen by the audience and the vicious cycle starts to work again (Rapee & Heimberg, 1997).
Previous studies indicated that people with social phobia generally evaluate the external feedbacks in a negative way. They focus on and exaggerate negative feedback more than people without social phobia (Rapee & Heimberg, 1997). It has been found that people with social phobia underestimate their performance in social situations compared to nonclinical people (Rapee & Lim, 1992). It has also been found, however, that this underestimation can be successfully changed with interventions. Treatment studies have indicated that people with social phobia have more realistic perceptions of their own performance, after receiving cognitive behavioral therapy (Taylor, 1996) and video feedback of performance (Rapee & Hayman, 1996).
On the other hand, it is possible that people with social phobia may actually perform poorly, because of their anxiety or because of social skills deficits. Recent research in this area has indicated that those people with social phobia actually have social performance deficits (Voncken, Bogels, 2008). The same study indicated that they perform worse in specific situations. Subjects with social phobia had performance problems not during a presentation for a group, but they did during a conversation with another individual. The researchers stated that during the presentation, the patient was in control of the situation. However, during the conversation, which requires interaction and more sensitive social behaviours such as listening, showing interest, smiling, or probing, the person might not have the feeling of being in control. These findings are important for treatments of the disorder. If the person with social phobia has real impairments in social behaviours, because of a lack of knowledge or experience, teaching those interpersonal skills might be one of the important elements of the treatment. However, it is still not clear whether these social deficits are be the cause or the consequence of social phobia, and more research is needed to establish which of the two is correct.
2.2. Etiological Factors While the cognitive model from Rapee and Heimberg (1997) can explain the cognitive processes which occur during the threat appraisal, it does not very well explain individual differences in threat appraisal. In a recent review, research findings on the etiology of social phobia were summarized (Rapee & Spence, 2004). Two main groups of factors which 10
contribute to the etiology of social phobia were distinguished: internal (genetic, temperament, cognitive and social skills deficits) and environmental factors (parent/child interaction, aversive social experiences and negative life events).
It is generally accepted that genetic factors play an important role in the development of anxiety disorders. However, their importance for social phobia has only been examined recently. Although previous genetic studies have found an inherited genetic predisposition to anxiousness in general rather than specific to social phobia (Hudson & Rapee, 2000), more recent studies have indicated a moderate significant genetic contribution to the development of social phobia (Rapee & Spence, 2004).
One area of research has focused on temperament styles and behavior inhibition, which was defined as reactions of withdrawal, avoidance and shyness in novel situations (Garcia et al., 1984). Findings of this research indicate that the prevalence rate of social phobia in parents of behaviorally inhibited children is significantly higher than in other people (Rosenbaum et al., 1991). Furthermore, behaviorally inhibited children have been found to have more social anxiety disorders compared to uninhibited children (Biederman et al., 1990). However, an anxious temperament, such as behavioral inhibition has not been found to be a specific risk factor for social phobia but rather for anxiety disorders in general.
Environmental factors can also play an important role in the etiology of social phobia. Many studies have found an increased risk for social phobia in the relatives of people with social phobia (Fyer et al., 1995). This familial transmission of social phobia may be related to the shared family environment. Among the environment factors, parent-child interactions have been examined in several studies. These studies have suggested that parental overprotection, parental rejection, and emotional distance between parents and children may play a role in the etiology of social phobia (Neal & Edelmann, 2003; Rapee & Spence, 2004).
Another environmental factor that has been examined in several studies is aversive social experiences. According to some studies, people with social phobia have experienced traumatic social experiences which have led to negative images of the self (Rapee and Spence, 2004). However, research in this area is scarce and is based on retrospective research, which may include biased reports of those early experiences (Rapee & Spencer, 2004). Moreover
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these factors influence the development of many other mental health disorders, besides social phobia. Thus, more prospective research is needed to understand the origins of social phobia.
3. Epidemiology 3.1. Prevalence and Incidence
Epidemiological studies estimate the lifetime prevalence of social phobia to be between 2.4% and 13% (Alonso et al., 2004; Kessler et al., 2005) . Although there is no exact estimate, due to the use of different diagnostic criteria and different assessment instruments, (Turner et al., 1992) social phobia is generally recognized as being highly prevalent (Davidson et al., 1994; Kessler et al., 1994; Furmark et al., 1999). Social phobia is more prevalent in women than in men, in younger people than in older people, in people who have never been married or are separated than in people who are married, in people with little education than in people with high education, and in people with low income than in people with high income (Chalebly, 1987; Davidson et al, 1993; Fehm et al., 2005; Furmark et al., 1999; Grant et al., 2005; Heimberg et al., 2000; Schneier et al., 1992).
In general, social phobia typically has an age of onset in the late childhood and early to middle adolescence (de Graaf, 2003; Ost, 1987; Kessler et al., 2005; Schneier et al., 1992). However, there are some studies that found earlier ages of onset, even as young as eight years (Turner & Beidel, 1989). People with social phobia commonly report a long duration of illness, ranging from 10 to 29 years (DeWitt et al., 1999; Chartier et al., 1998). Although social phobia tends to have a chronic course, there are studies which examine the recovery from social phobia. Reported recovery rates vary between 27% and 85% in community studies with an average duration of the disorder of 29 years (Degade & Angst, 1993; Chartier et al., 1998; DeWitt et al., 1999). However, in clinical settings long-term rate of recovery for social phobia was found to be only 35%, which is lower than those of other anxiety disorders (e.g. GAD: 50%; major depressive disorder: 72%; panic disorder without agoraphobia: 82%; Keller, 2006). Factors that predict recovery are high level of education, being brought up in a small town, having no more than one sibling, being employed, having an onset of social phobia after age seven, having three or less symptoms of the disorder, and not having a comorbid psychiatric disorder or another health problem (Chartier et al., 1998, DeWit et al., 1999).
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There is a lack of studies examining the incidence of social phobia. To our knowledge, only three prospective community-based epidemiological studies have examined the incidence of social phobia: the Netherlands Mental Health Survey and Incidence Study (NEMESIS) (Bijl et al., 2002; de Graaf et al., 2002) the Epidemiologic Catchment Area Study (ECA) in the USA (Wells et al., 1994; Neufeld et al., 1999) and the Early Developmental Stages of Psychopathology (EDSP) study in Germany (Beesdo et al., 2007). According to the NEMESIS, social phobia has a 1.0% 12-month first incidence rate ( Bijl et al., 2002). The most recent ECA data report an incidence rate of 4-5 / 1000 life years (Neufeld et al., 1999). The EDSP reported a cumulative incidence rate of 11.0% for social phobia in the first three decades of life. The ECA study reported a number of risk factor factors associated with a higher incidence rate, including: being female, having little education, not being married, and having comorbid mental or physical symptoms (such as nervousness, headache, palpitations, other phobias, binge patterns of alcohol consumption, dysthymia, and schizophrenic symptoms). However, these predictive factors were not confirmed in the EDSP study. In this study only baseline depressive and panic disorders appeared to be significant predictors of social phobia (Neufeld et al., 1999).
Knowledge about risk factors for social phobia can be very useful for the development of preventive interventions for social phobia. However, considering the lack of sufficient knowledge on this subject, more research is needed.
3.2.Comorbidity Social phobia without other comorbid mental disorders is rare and usually high rates of comorbidity are reported (Alonso et al., 2004; Chartier et al., 2003). Both epidemiological studies and clinical studies have shown that at least half of the social phobia patients had another DSM-IV disorder (Schneier et al., 1992; Kessler et al., 1999; Merikangas et al., 1995). The most reported comorbid disorders are: other anxiety disorders (about 33%) , mood disorders (about 30-50%) and substance use disorders (about 25%; Schneier et al., 1992, Merikangas et al., 1995).
Among the other anxiety disorders, generalized anxiety disorder appears to be the most common comorbid disorder (Mennin et al., 2000) although other phobic disorders such as agoraphobia (Schneier et al., 1992, Chartier et al., 2003), and simple phobia (Schneier et al., 1992) also occur frequently among people with social phobia. The association between social 13
phobia and substance abuse disorders is more complicated. Some studies showed substantial comorbidity rates (Morris, Stewart & Ham, 2005) while others indicated a moderate to low comorbidity with social phobia (Chartier et al., 2003; Davidson et al., 1993). Differences in methodology, population, diagnosis and the methods of dealing with missing data may contribute to this variation in comorbidity rates (Chartier et al., 2003). In addition, the definition of comorbidity and the considered time period may have contributed to this variation (Wittchen, 1996). However, in a recent review, it is stated that the presented comorbidity rates for alcohol use disorders in subjects with social phobia may be underestimated (Morris et al., 2005). The subjects with social phobia may not accept their problems due to alcohol use because of the fear of negative evaluation (Morris et al., 2005). Another factor contributing to the low comorbidity rate may be related to the group therapies for substance use disorders. As it lies in the definition of social phobia, people with social phobia would not be eager to participate in a group therapy in where they will be exposed to unfamiliar people (Marshall, 1994).
As indicated earlier, social phobia has an early age of onset and therefore precedes the comorbid disorder in most cases (Graaf de et al. 2003; Kessler, et al., 1999, Magee et al., 1996; Ruiter, Rijken, Garssen, van Schaik, & Kraaimaat, 1989;). In a population study, social phobia was found to be the preceding disorder in 32% of comorbid anxiety disorders, 71% of comorbid mood disorders, and 80% of comorbid substance dependence and abuse disorders (Chartier et al., 2003). Moreover, in NEMESIS it is reported that among males with lifetime major depression, 62.7% developed social phobia before the onset of major depression while 54.9% of females with major depression had social phobia before major depression has started (Graaf de et al., 2003). This earlier onset of social phobia suggests that social phobia may be a risk factor for additional mental health disorders (Schneier et al., 1992; Chartier et al., 2003).
3.3 Burden of Social Phobia 3.3.1Functional Impairment and Quality of Life Anxiety disorders constitute a disabling group of disorders. In the Netherlands they cause serious disability and rank second in a list of 49 selected mental and physical disorders, directly after coronary heart disease (Bohn, Stafleu, Van Loghum, & Houten, 2002; Melse, Essink-Bot, Kramers, & Hoeymans, 2000). For social phobia substantial functional impairments have been reported in several major activities, including; work, school, 14
volunteering, childrearing, relationships with neighbours, volunteering and personal care (Stein & Kein, 2000). It is also reported that people with social phobia are more likely to have more dissatisfaction with their own functioning and as a result report a low quality of life (Ware & Sherbourne, 1992; Ware Snow, Kosinski, & Gandek, 1993).
The disease burden of social phobia appears to be associated with the number of social fears. Subjects with higher numbers of feared social situations suffer more from social, functional and psychological disability (Vriends 2006). Consequently, the burden associated with the generalized social phobia subtype seem to be higher than that for the more isolated social fears (Stein & Kein, 2000; Kessler et al., 1998). Patients with the generalized subtype appear to be more anxious and depressed, have lower performance on behavioural and cognitive tasks, and report a lower quality of life compared to the non-generalized subgroup (Heimberg et al., 1990; Safren et al., 1996). In addition, comorbidity is also found to be related to the severity of the disorder and hence to the burden associated with it (Wittchen et al., 2000). Furthermore, suicidal ideation has been found to be more prevalent in social phobics with comoribid depression (Schneier et al, 1992; Davidson et al, 1993).
5.2. Costs of Social Phobia
With a lifetime prevalence of 16.6%, anxiety disorders are among the most prevalent psychiatric disorders (Somers et al., 2006). They are found to be associated with huge economic costs. In terms of total costs, panic disorder appeared to be the most expensive anxiety disorder (Konnopka et al., 2008). However, along with specific phobias and agoraphobia, social phobia has also been shown to be associated with substantial economic costs (Konnopka et al., 2008; Löthgren, 2004; Greenberg et al., 1999; Smit et al., 2006). The scarce research findings in this area suggest that social phobia is associated with more frequent use of prescribed medication (Patel et al., 2002), higher levels of GP visits (Patel et al, 2002), higher levels of unemployment (Patel, et al., 2002; Wittchen et al., 1996), more absenteeism from work (Lecrubier et al., 2000; Wittchen et al., 1996), increased financial dependency (Schneier et al., 1992; Leon et al., 1995), and decreased work productivity (Kessler et al., 1997; Wittchen et al., 2000).
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Until now very few studies have examined the relationship between the different types of social fears and economic costs, nor between the number of social fears and economic costs (Wittchen et al., 2000, Stein et al., 2000).
5. Treatment 5.1. Help Seeking Behaviour Despite the increased functional impairment and decreased quality of life, many aspects of help-seeking behavior of social phobics remain unclear. Some studies report increased helpseeking behaviour in subjects with social phobia (Schneier et al., 1992), but there are also studies which report decreased help-seeking behaviour (Magee et al., 1996). It has also been suggested that subjects with social phobia who receive professional help, seek mainly help for their comorbid mental illnesses, but not for social phobia (Davidson, Hughes, George, & Blazer, 1993; Lepine, et al., 1995). In the National Comorbidity Survey, it was found that people with social phobia and a comorbid disorder seek help more often than those without a comorbid mental disorder (Magee et al., 1996).
Several factors may contribute to decreased help seeking behaviour of people with social phobia. First of all, social phobics may attribute their symptoms to their personality (such as shyness) and do not consider the symptoms as part of a disorder. This is strengthened by the early onset of most cases of social phobia (Magee et al., 1996). Because they consider their social phobia as a part of their personality, they are less inclined to seek help. Second, people may not know that social phobia can be successfully treated by psychotherapy or pharmacotherapy (Feske & Chambless, 1995). Another related factor contributing to the decreased help seeking behaviour may be ‘avoidance behaviour’. A person with social phobia may view psychotherapy as a social interaction which induces anxiety and which is therefore avoided. Furthemore, they might be anxious about stigmatization (Davidson et al., 1993).
5.2. Treatment Psychological interventions have been found to be effective in the treatment of social phobia (Rodebaugh et al., 2004), also at the longer term (Feske & Chambless, 1995). The most widely used psychological treatment for social phobia is cognitive behaviour therapy, which can include exposure, cognitive restructuring, applied relaxation, social skills training or a combination of them (Taylor, 1996; Federoff & Taylor, 2001). Several controlled studies 16
have indicated that all forms of cognitive behaviour therapy are effective in treating social phobia (Taylor, 1996). It is not yet clear whether or not one component of CBT is more effective than other (combinations of) components. While two earlier meta-analyses found that adding cognitive restructuring to exposure therapy did not improve the treatment outcome (Feske & Chambless, 1995; Gould et al., 1997), in another meta-analysis, Taylor (1996) it was found that adding cognitive restructuring to exposure did provide some benefit.
Next to psychological treatments, the effectiveness of pharmacotherapy has also been demonstrated well. Most commonly prescribed are: benzodiazepines, monoamine oxidase inhibitors and selective serotonin reuptake inhibitors (SSRIs; Federoff & Taylor, 2001; Gould et al., 1997). Among them, benzodiazepines and SSRIs were found to be the most effective ones in the short-term (Federoff & Taylor, 2001; Gould et al., 1997). In conclusion, although social phobia is a debilitating disorder, cognitive behavioural interventions and pharmacological interventions have been found to be effective in the treatment of social phobia.
6. Aims and structure of this thesis Although social phobia is among the most common mental disorders (Kessler et al., 1994), more research is needed about incidence rates, risk factors associated with onset, and economic costs. The main aim of the present thesis is to contribute to this body of knowledge. First, we want to describe the demographic and clinical characteristics of the people with social phobia. We have used data from NEMESIS to examine the epidemiology of social phobia in the general Dutch population (Chapter 2). Based on previous research (Schneier et al., 1992; Kessler et al., 1999), we hypothesized that comorbidity with other DSM mental disorders would be significantly higher in subjects with social phobia, while the quality of life would be lower. Moreover, related to the high comorbidity rates and the decreased quality of life, we expected an increased service utilization. In this study, we also examined whether social phobia exits on a continuum of increasing severity with the number of social fears ranging from one social fear to multiple social fears.
Apart from the disease burden of social phobia, previous research also indicated that social phobia is associated with increased economic costs. In order to examine whether people with social phobia have increased medical and non-medical costs compared to people without any mental disorder, we again used data of NEMESIS. Because we found that the different types 17
of social fears and the number of social fears were related to the level of disease burden, we also studied the relationship between the economic costs and the type and number of social fears. In addition, we explored the economic burden of subthreshold social phobia. These findings are discussed in chapter 3.
As described above, only few studies have examined the incidence of social phobia. Therefore, we examined risk factors for the incidence of social phobia in the prospective data of NEMESIS. In order to identify high-risk groups for cost-effective prevention at the earliest stage, a methodology which is developed by Smith et al. (2004) was applied (Chapter 4). This chapter provides both the incidence of social phobia in the general Dutch population and a model for the prevention of social phobia.
Up to here, in order to investigate these research questions we used the data from the NEMESIS (the Netherlands Mental Health Survey and Incidence Study; N=7076) which was based on a prospective, stratified, random sampling procedure. The data were collected in three waves (1996, 1997, and 1999). Social phobia was assessed according to DSM-III-R with the Composite International Diagnostic Interview (CIDI). The details about sample, instruments and analysis which are specific to each study are described in each of the chapters (chapter 2 to 4).
Several meta-analyses have found evidence that psychological treatments such as exposure, cognitive restructuring, social skills training, and applied relaxation are effective in the treatment of social phobia. However, several of these earlier meta-analyses included nonrandomized and uncontrolled studies, which may have resulted in an overestimate the effect sizes of the treatments. In order to assess the effectiveness of psychological treatments, we conducted a new meta-analysis. This meta-analysis was limited to randomized controlled trials and several recent studies were included, which were not included in earlier metaanalyses. In order to explore possible sources of heterogeneity, we also conducted several series of subgroup analyses (which were not conducted in previous meta-analyses). We selected thirty studies which compared a psychological intervention to a control condition (Chapter 5).
Finally, in chapter 6 the findings from these studies are discussed and suggestions for future research are given. 18
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Chapter 2
Social Phobia and number of social fears, and their association with comorbidity, health-related quality of life and help seeking: A populationbased study Abstract Objectives Community based data were used to examine the association between social phobia and comorbidity, quality of life and service utilization. In addition, the correlations of the number of social fears with these domains were. Method Data are from the Netherlands Mental Health Survey and Incidence Study (NEMESIS) (N=7076). Social phobia was assessed according to DSM-III-R with the Composite International Diagnostic Interview (CIDI); quality of life was assessed according to the Short-Form-36 Health Survey (SF-36). Results The 12-month prevalence of social phobia was 4.8%. Being female, young, low educated, a single parent, living alone, not having a paid job and having a somatic disorder are associated with 12-month social phobia. Mean and median ages of onset of social phobia were 19.3 and 16.0 years, respectively, and mean and median duration were 16.8 and 14.0 years, respectively. 66% of respondents with social phobia had at least one comorbid condition. 12-month social phobia was significantly related to lower quality of life and higher service utilization. The mean number of feared social situations was 2.73 out of the 6 assessed. As the number of social fears increases, comorbidity and service utilization increases, and the quality of life decreases. Conclusions These findings suggest as the number of feared social situations increases, the burden of social phobia rises. In other words, like comorbidity or decreased quality of life, the number of social fears is also an important indicator of the severity of social phobia. We conclude that from a public health perspective, mental health care givers should pay attention to the number of social fears in order to check the severity of social phobia.
This chapter has been published as: Acarturk, C; de Graaf, R; van Straten, A; ten Have, M; Cuijpers, P (2008). Social phobia and number of social fears, and their association with comorbidity, health related quality of life and help seeking: a population-based study. Soc Psychiatry Psychiatr Epidemiol.43, 273-279
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Introduction Social phobia is a highly prevalent disorder (Davidson, Hughes, George & Blazer, 1993; Furmark, 2002; Furmark et al., 1999;,Grant et al., 2005; Kessler et al., 2005; Kessler et al., 1994; Kringlen, Torgersen, & Cramer, 2001; Offord, et al., 1996), which is associated with huge loss in quality of life, (Stein & Kean, 2000; Wittchen, Fuetsch, Sonntag, Muller & Liebowitz, 2000) enormous economic costs, (Patel, Knapp, Henderson & Baldwin, 2002), high levels of service use, (Magee, Eaton, Wittchen, McGonagle & Kessler, 1996; Stein & Kean, 2000), serious functional impairments in the areas of education, social and occupational domains (Davidson et al., 1993; Kessler, Stein & Berglund, 1998), and high comorbidity rates with other anxiety and mood disorders (Chartier, Walker & Stein, 2003; Kessler, Stang, Wittchen, Stein & Walters, 1999).
It is not yet clear whether specific subtypes of social phobia can be distinguished. In clinical samples, several types of social phobias have been found, with one group of patients suffering exclusively from performance fears (such as speaking in public), while others suffer from a broader range of fears, including both performance fears and interactional fears (such as meeting new people). (Kessler et al., 1998; Vriends, Becker, Meyer, Michael & Margraf, 2007) Generalized social phobia has been defined as a social phobia in which both performance fears and interactional fears occur together. (Safren, Heimberg, Brown & Holle, 1996). However, it has also been defined as a social phobia in which multiple social fears occur together.
Although there is some evidence that different types of social phobia do indeed exist, it has also been suggested that there is stronger evidence that social phobia should be seen as a unidimensional condition, (Lepine & Lellouch, 1995; Safren et al., 1996; Stein et al., 2000) in which an increasing number of feared situations is related to increased functional impairments and psychological problems (Bijl, Ravelli & van Zessen, 1998; Furmark, Tillfors, Stattin, Ekselius & Fredrikson, 2000; Stein & Deutsch, 2003; Stein et al., 2000). This would suggest that social phobia exists on a continuum of severity.
Whether social phobia exists on a continuum of increasing severity with the numbers of fears, however, has not been studied conclusively yet. Some studies have examined whether evidence could be found for such a continuum by examining the relationship between severity
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and functional impairment (Bijl et al., 1998; Safren et al., 1996; Stein et al., 2000). However, most of these studies used clinical samples, and have not examined other relevant indicators of severity, such as service utilization, overall quality of life, and comorbidity.
We examined these issues in the data of the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a large, representative, population-based study in which the presence of social phobia and other mental disorders was determined by well-validated diagnostic interviews. More specifically, we examined whether we can find support for the hypothesis that social phobia exists on a continuum of increasing severity with the numbers of fears ranging from one social fear to multiple social fears, and whether this number of social fears is related to quality of life, comorbidity with other Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev., American Psychiatric Association, 1987) Axis I disorders and service utilization.
Methods Sample NEMESIS was based on a multistage, stratified, random sampling procedure (Bijl, van Zessen, Ravelli, de Rijk & Langendoen, 1998a). Initially, a sample was drawn of 90 Dutch municipalities stratified on the basis of urbanization and adequate dispersion over the 12 provinces in the Netherlands. Secondly, a sample of private households (addresses) from post office registers was gathered. The number of households selected in each municipality was determined by the size of its population. The third step was to choose which individuals to interview. The residents of the selected households were sent a letter of introduction signed by the Minister of Public Health requesting them to take part. Afterwards, the interviewers contacted the residents by telephone. Households with no telephone or with ex-directory numbers (18%) were visited in person. One respondent with the most recent birthday was randomly selected in each household, on condition that s(he) was between 18 and 64 years of age and sufficiently fluent in Dutch to be interviewed. Persons who were not immediately available because of circumstances such as hospitalization, travel or imprisonment were contacted later in the year. If necessary, to make a contact, the interviewers made a minimum of ten calls or visits at a given address at different times of the day and week. In the first round of the data collection, from February through December 1996, a total of 7,076 persons were interviewed (response rate of 69.7%) . Refusal was the most important reason for non-
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response. The sample reflected adequately the Dutch population in terms of gender, civil status and urbanization level (Bijl et al., 1998a). The data was collected by 90 experienced interviewers. All of the interviewers went through a 3 day training course in recruiting respondents and computer assisted interviewing. After that, a 4 day course of training focused specifically on the content of NEMESIS and the use of CIDI at the WHO-CIDI training center of the Academic Medical Center in Amsterdam was given.
Measures Diagnoses of mental disorders The diagnoses were based on DSM-III-R Axis I (APA, 1987; Robins et al., 1988). The Composite International Diagnostic Interview (CIDI) version 1.1 (computerised version) was used to determine the diagnoses (World Health Organization [WHO], 1990) The CIDI is a structured interview developed by the World Health Organization (Smeets & Dingemans, 1993; Wittchen et al., 1991), on the basis of Diagnostic Interview Schedule (DIS) and the Present State Examination (PSE). It was designed for use by trained interviewers who are not clinicians. The CIDI is now being used worldwide, and WHO field trials have documented acceptable reliability and validity for nearly all diagnoses (Robins et al., 1988; Spitzer, Williams, Gibbon & First, 1992; Wittchen et al., 2000) with the exception of acute psychotic presentations. Whenever psychotic symptoms were detected, subjects were reinterviewed by trained interviewers with the Structured Clinical Interview for DSM-III-R, an instrument that is reliable and valid for diagnosing schizophrenia (Spitzer et al., 1992).
The CIDI was used to determine the lifetime, 12-month, and one-month prevalence of mood, anxiety, substance-related and eating disorders. In the current study, we used the 12-month data of social phobia, as well as the 12-month data of comorbid anxiety disorders (panic disorder, agoraphobia, simple phobia, obsessive compulsive disorder, generalized anxiety disorder), mood disorders (depression, dysthymia, bipolar disorder), and substance use disorders (alcohol, drug, or any substance abuse or dependence). Because of the low prevalence of eating disorders and psychotic disorders, these disorders were not examined in this study. For comorbidity patterns, the hierarchical rules of DSM-III-R were ignored. Applying the hierarchical rules would have resulted in social phobia subjects being missed if they also had another DSM-III-R disorder which has the hierarchical precedence (Bijl, de Graaf, Ravelli, Smit & Vollebergh, 2002).
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Number of social fears Consistent with the DSM-III-R, respondents were asked if they had excessive or unreasonable fear in six social situations (speaking in public, talking to people when you might have nothing to say or might sound foolish, talking in front of a small group, using public toilets, eating or drinking in public places and writing while being observed), and tried to avoid it or felt intensely anxious, in the past 12 months. For each subject with a 12month social phobia, we calculated the total number of social fears he or she had. Quality of Life was assessed with the 36 item Short Form-36 Health Survey (SF-Į (Ware & Sherbourne, 1992; Ware, Snow, Kosinski & Gandek, 1993). A higher score indicates better functioning. The SF-36 has eight subscales. The ‘physical functioning’ scale (10 items) measures the health related limitations regarding daily activities such as bathing, getting dressed and going up and down stairs. The ‘role limitations due to physical problems’ (four items) and ‘role limitations due to emotional problems’ (three items) scales assess problems occurring in the previous 4 weeks that arose from physical health symptoms or emotional difficulties. The ‘vitality’ scale (four items) measures lack of energy and fatigue. ‘Social functioning’ scale (two items) records limitations regarding social activities such as visiting friends and relatives. The ‘pain’ scale (two items) pertains to the amount of bodily pain and its limiting effect. The ‘general health perception’ scale (five items) measures the individual’s own assessment of his or her general health. The last scale ‘mental health’ (five items) measures the feelings of depression or nervousness.
Service Utilization Questions were asked about help from primary care (general practitioner, company physician, crisis care, general social worker, home care/district nursing), informal care (alternative care provider, self-help group, traditional healer, telephone help line, physiotherapist/haptonomist) and from mental health care (community mental health care institute, psychiatric outpatient clinic of a psychiatric or general hospital, independent psychiatrist or psychotherapist) within the past 12 months, in order to assess whether the respondents had sought help for their psychological or drug/alcohol related problems.
Demographic variables Gender, age, level of education (low, medium, high), and cohabitation status (living alone or not).
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Analyses We examined the relationship between the number of social fears and comorbidity with logistic regression analyses in which the presence (yes/no) of the comorbid disorder was used as dependent variable, and the number of social fears was entered as predictor while controlling for demographic variables.
In order to examine the effect of the presence of social phobia and the number of social fears on the domains of quality of life, we conducted two separate series of linear regression analyses in which the domains of quality of life were used as the dependent variable. In the first analyses, the presence of social phobia was entered after controlling for sociodemographic variables. Then, in the second analyses, the number of social fears was entered as a continuous predictor, while controlling for demographic variables.
The relationship with help-seeking was examined with a logistic regression analysis in which help-seeking (yes/no) was used as dependent variable, and the number of social fears was entered as predictor.
The data were weighted in all analyses to adjust for different response rates in different population groups for the characteristics that are associated with the occurrence of psychiatric disorders such as gender, age, marital status (2 categories: married, not married) and urbanization (seven categories). The weighting procedures have been described in more detail elsewhere (Bijl et al., 1998b). Furthermore, because earlier research has shown that several demographic variables are associated with social phobia, we adjusted for demographics in all analyses (Davidson et al., 1993; Furmark et al., 1999; Kessler et al., 2005).
Results Prevalence of social phobia and number of social fears The 12-month prevalence of social phobia was 4.8%, while the mean age of onset was 19.3 years (S.D. =11.7). The mean duration of lifetime social phobia was 19.2 years (S.D. =13.5). The 12-month prevalence of social phobia was significantly associated with being female, of a younger age, being less well educated, and living alone (Table 1).
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Among the respondents with 12-month social phobia, the mean number of feared social situations was 2.73 (S.D. =1.35) out of 6 situations. Twenty-one point zero percent of social phobics feared only one social situation, while 25.9% feared two situations, 26.8% feared three situations, and 25.9% feared four to six social situations.
Table 1. Association (Odds Ratios) between demographic variables and 12-month social phobia:
Demographics - Female gender - Level of education
- Living Alone - Age: M (SD)
Low Medium High
Social Phobia (%) 63.2 12.1 47.8 40.0 25.1 40.2 (11.6)
No Social Phobia (%) 48.7 6.0 35.9 58.1 17.3 41.2 (12.2)
OR (unadj) 1.81 1 (ref) 0.66 0.34 1.60 0.99
95% CI 1.45-2.28 0.46-.94 0.24-.49 1.24-2.06 0.99-1.00
OR* (adj) 1.74 1 (ref) 0.60 0.28 1.81 0.99
95% CI 1.39-2.19 0.42-0.87 0.19-0.42 1.40-2.35 0.98-0.99
* Odds ratios have been controlled for gender, age, level of education, and cohabitation status
For respondents with social phobia, public speaking was the most common fear (82.0%). The second most common fear was also a speaking fear, “fear of speaking when you might have nothing to say or might sound foolish” (61.1%). Third was talking in front of a small group (55.0%), followed by writing while being observed (29.7%), eating and drinking in public (21.6%), and using public toilets (18.0 %).
Association between social phobia and number of social fears, and comorbidity As can be seen in Table 2, subjects with social phobia have a significantly increased chance of having one or more of the studied comorbid mental disorders, with the exception of alcohol and drug abuse. About two-thirds (66.2%) of the respondents with social phobia reported at least one other mental health disorder. Social phobia is especially strongly associated with obsessive compulsive disorder (OR: 14.26, 95% CI: 6.95-29.26), bipolar disorder (OR: 13.09, 95% CI: 8.49-19.99), agoraphobia without panic disorder (OR: 12.76, 95% CI: 8.51-19.14), and panic disorder (OR: 12.74, 95% CI: 8.95-18.13).
31
17.8 12.4 37 16.7 4.3 61.8
29.3 20.3 11 40.6
4.6 7.5 0.6 5 15.2
Any disorder - > 1 DSM III-R disorder
Anxiety Disorders - Panic disorder - Agoraphobia - Simple Phobia - GAD - OCD - Any Anxiety Disorder
Mood Disorders - Major Depression - Dysthymia - Bipolar Disorder - Any Mood Disorder
Substance related disorders - Alcohol Abuse - Alcohol Dependence - Drug Abuse - Drug Dependence -Any Substance Related Disorder 4.6 3.5 0.5 0.6 8.6
4.7 2.2 0.9 6.4
1.4 1.0 5.6 1.8 0.3 15.7
present No SP % 19.7
N.S. 2.67*** N.S. 7.63 2.43***
7.32*** 9.11*** 13.09*** 8.76***
12.74*** 12.76*** 8.63*** 8.94*** 14.26*** 8.39***
6.91***
or not OR a)
4.23-13.76 1.75-3.37
1.72-4.17
5.62-9.55 6.62-12.53 8.49-19.99 6.87-10.92
8.95-18.13 8.51-19.14 6.72-11.09 6.34-12.62 6.95-29.26 6.62-10.62
5.40-8.85
95% CI
32
a) Odds ratios have been controlled for sex, age, level of education, and cohabitation. * p ** p ***p
SP SP % 66.2
6.5 10.0 4.3 16.5
18.5 7.0 5.0 26.6
4.5 4.2 23.5 10.0 0.7 38.1
Number 1 % 58.0
2.0 1.2 3.3 6.5
27.2 14.7 10.1 37.9
12.6 9.6 29.8 22.8 1.2 55.4
of fears 2 % 61.9
5.8 10.6 5.4 18.4
30.1 26.0 16.7 45.9
22.7 10.3 41.8 8.0 4.0 68.4
3 % 75.9
6.4 6.6 2.4 10.1 23.1
31.4 20.1 9.8 45.2
17.2 11.0 54.4 24.8 10.8 77.7
4 % 92.0
1.7 10.1 2.5 3.9 16.5
49.9 44.9 12.9 56.4
43.3 40.0 49.0 27.6 11.7 92.4
5/6 % 96.6
N.S. N.S. 4.12 N.S. N.S.
1.37*** 1.65*** N.S. 1.35***
1.75*** 1.84*** 1.37*** N.S. 2.43*** 1.87***
1.88***
OR a)
Table 2. Proportion of subjects with 12-month social phobia with comorbid mental disorders, according to number of social fears
.73-23.32
1.13-1.61
1.14-1.64 1.33-2.05
1.48-4.00 1.51-2.31
1.39-2.20 1.41-2.40 1.14-1.65
1.49-2.37
95% CI
Table 2 shows that the level of comorbidity with mood and anxiety disorders increases significantly with the number of social fears. About 38% of the socially phobic subjects with one social fear have a comorbid anxiety disorder, and this percentage increases steadily with an increasing number of social fears. About 92% of the subjects with five or six fears have a comorbid anxiety disorder. About 27% of the socially phobic subjects with one social fear have a comorbid mood disorder, while 56% of the subjects with five or six fears have a mood disorder. For the separate anxiety and mood disorders significant linear trends were found, with the exception of generalized anxiety disorders, and bipolar disorders. We also found few indications that the number of social fears was associated with comorbid substance-related disorders. For illustrative purposes, we have graphically presented the association between number of social fears and comorbid mood, anxiety and substance-related disorders in Figure 1.
Fig. 1 Comorbidity related to the number of social fears
Percentage of Comorbidity
120% 100%
Any Anxiety Disorder
80%
Any Mood Disorder
60%
Any Substance Use Disorder
40%
Any 12-months comorbidity
20% 0% 1
2
3
4
5
Number of Fears
33
Association between social phobia and number of social fears, and health-related quality of life When we compared subjects with a social phobia to those without, we found that social phobics had significantly lower scores in all eight dimensions of functioning (Table 3). As expected, an increasing number of social fears was associated with a decreased level of health-related quality of life. However, from table 3, it can be seen that social phobics with only one social fear have no dramatically different scores than the subjects without social phobia.
Association between social phobia and number of social fears and service utilization The association between social phobia and help-seeking is presented in Table 4. As could have been expected, subjects with a social phobia have sought treatment more often than subjects without social phobia, and this is true for help from primary care, mental health care, and informal care. A higher number of social fears was significantly associated with more help-seeking behaviour. A total of 52% of subjects with one social fear sought help, while 93% of the subjects with five or six social fears sought help. For illustrative purposes, we have graphically presented the number of social fears and the percentage of subjects who sought help (Figure 2).
34
mean(SD) mean(SD) mean (SD) mean(SD) mean(SD) mean(SD)
Psych. Role Func.
Vitality
Psych. Health
Social Functioning
Pain
General Health
86.1 (20.5) 73.1 (38.3) 71.1 (40.6) 55.6 (21.8) 63.9 (21.1) 75.6 (25.2) 75.3 (26.1) 61.5 (21.1)
92.3 (15.3) 86.4 (29.2) 93.1 (21.6) 72.2 (17.7) 82.7 (14.0) 90.3 (17.1) 85.8 (21.2) 75.0 (17.4)
or not No SP
-.113**
-.059**
-.123**
-.189**
-.133**
-.152**
-.058**
-.050**
Beta a
.012
.003
.014
.034
.017
.022
.003
.002
R2 Change a b
92.3 (12.8) 86.2 (27.4) 82.8 (33.7) 63.4 (18.1) 72.3 (15.7) 87.1 (17.1) 86.2 (18.2) 67.2 (18.1)
Number 1
83.6 (22.5) 73.0 (39.6) 72.9 (38.8) 54.9 (23.7) 65.4 (21.4) 76.8 (26.0) 75.4 (26.2) 61.4 (20.1)
of fears 2
88.1 (18.1) 76.5 (34.2) 76.0 (36.7) 57.8 (18.9) 64.5 (19.2) 75.8 (25.4) 75.4 (24.8) 63.5 (19.3)
3
82.7 (26.3) 54.7 (45.4) 61.1 (45.2) 51.6 (19.2) 61.1 (21.5) 67.2 (24.6) 66.5 (32.8) 57.6 (23.9)
4
78.7 (23.4) 59.8 (44.6) 44.2 (47.4) 41.7 (26.0) 46.4 (23.3) 59.7 (27.2) 63.6 (26.9) 50.8 (25.3)
5/6
-.147**
-.205**
-.267**
-.237**
-.179**
-.205**
-.193**
-.113*
Beta a
.019
.037
.063
.050
.029
.037
.033
.011
R2 Change a b
*p **p
b
35
R2 Change and beta-coefficients have been controlled for sex, age, level of education, cohabitation and comorbidity with any other DSM III-R disorder R2 Change indicates how much of the overall variance is explained by the presence of social phobia or the number of social fears after the effects of sociodemographics and other DSM-III-R disorders are removed
mean(SD)
Physical Role Func.
a
mean(SD)
Physical Func.
SP present SP
Table 3. Quality of Life, as measured with the MOS-SF-36, in subjects with 12-month social phobia, according to number of social fears
Or not No SP % 27.0 9.8 16.6 31.2 4.81* (3.81-6.08) 4.21* (3.30-5.37) 4.88*(3.88-6.14) 5.06* (3.96-6.46)
OR 1 a) 95% CI
b)
95% CI
2.70*(2.11-3.46) 2.44* (1.88-3.16) 2.54* (1.96-3.29) 2.81* (2.15-3.67)
OR 2
Number 1 % 45.4 21.4 27.9 52.0
of fears 2 % 64.6 33.1 46.5 68.4 3 % 64.6 30.2 44.0 73.7
4 % 80.8 37.7 70.6 84.7
5/6 % 91.0 63.0 83.7 92.8
36
0%
20%
40%
60%
80%
100%
1
3
4
Number of Fears
2
5
Fig. 2 Service utilization related to the social fears
b)
Mental Help
Informal Help
Primary Help
Any Help
Odds ratios have been controlled for gender, age, level of education, and cohabitation. Odds ratios have been controlled for gender, age, level of education, cohabitation and comorbidity with any other DSM-III-R disorder. * p
a)
- Primary Care - Informal Care - Mental Health Care - Any Help
SP present SP % 65.4 33.8 49.0 71.0
Table 4. Service use in subjects with 12-month social phobia, according to number of social fears
Percentage of Service Utilization
1.68*(1.37-2.05) 1.44*(1.20-1.72) 1.77*(1.46-2.14) 1.72*(1.39-2.14)
OR 1 a) 95% CI
b)
95% CI
1.49*(1.18-1.88) 1.47*(1.18-1.82) 1.28*(1.06-1.55) 1.62*(1.33-1.97)
OR 2
Discussion Epidemiological Results The 12-month prevalence rate (4.8%) in the present study was rather lower than the previous findings (6.7%-7.9%) conducted in Norway, Canada and United States of America which used DSM-III-R criteria and the CIDI (Furmark et al., 1999; Kessler et al., 1994; Kringlen et al., 2001; Offord et al., 1996). This may be clarified by two explanations. First, there might be cultural differences in psychiatric disorders also between the western countries. Second, the diagnostic instruments might be translated and administered in a somewhat different method in each country (Patel et al., 2002). In addition, other explanations could be the differences in sampling and research methods used. Our result for mean age of onset (19.3 years) is consistent with earlier community based studies (14.6 – 24.3 years) (Davidson et al., 1993; Grant et al., 2005; Lepine & Lellouch, 1995; Magee et al., 1996; Weissman et al., 1996). Similar to the previous results (Bijl et al., 2002; Davidson et al., 1993; Fehm, Pelissolo, Furmark & Wittchen, 2005), social phobia lasts a long time with a mean duration of 19.2 years in our sample
The demographic results of the present study are mainly consistent with the majority of the previous studies. Respondents who are female, younger, less well educated and not working are more likely to have social phobia (Chaleby, 1987; Davidson et al., 1993; Furmark et al., 1999; Grant et al., 2005; Heimberg, Stein, Hiripi & Kessler, 2000; Lepine & Lellouch, 1995; Magee et al., 1996). Furthermore, social phobia was found to occur more in single parents and those who live alone (Fehm et al., 2005; Schneier et al., 1992).
Our findings showed that social phobics were using primary care, informal care and mental health care to a greater extent compared to people without social phobia. Consistent with the previous research [8], we also found that they were using those care services not for phobic anxiety but for other complaints. It is possible that they fear scrutiny even in health care locations and prefer to present with physical complaints or other problems that are different from social phobia. Thus, we can suggest to health care professionals to check for underlying social phobia in those cases where they may have suspicions.
37
The Number of Social Fears We found clear indications that the number of social fears in subjects with social phobia is related to levels of comorbidity, to domains of health-related quality of life, and to helpseeking behaviour. The larger the number of social fears, the higher the chance of having a comorbid anxiety or mood disorder, poorer quality of life and an increased likelihood of helpseeking. This indicates that the number of social fears is clearly associated with indicators of disability.
Earlier research already demonstrated that the number of fears is associated with a decreased level of quality of life (Hankin, Fraley, Lahey & Waldman, 2005; Safren et al., 1996; Stein et al., 2000) and increased chance of comorbidity (Vriends et al., 2007), but this study is the first general population-based study that shows the number of fears is also related to higher levels of help-seeking in terms of primary, informal and mental health care services.
The ‘category versus dimension’ issue has been examined in many mental health disorders such as mood and personality disorders. Although this debate still continues, there is some evidence indicating that depression (Hankin et al., 2005), bipolar disorder II (Akiskal & Benazzi, 2006), and personality disorders (Skodol et al., 2005) may possibly be better understood as existing on a continuum, rather than as discrete categorical disorders. Moreover, in the definition of ‘generalized social phobia’, DSM-IV-R requires fears of most social situations which emphasizes the continuum of the disorder. Although, the present findings indicate that as the number of social fears increases, the burden of social phobia also increases, it is not enough to conclude that social phobia lies on a continuum with the present data. In order to claim that, the data needs to include also the subjects under the diagnostic threshold of social phobia.
The present findings show that there might be thresholds in number of social fears in terms of severity of the disorder. For example, in service utilization there could be a threshold between having three or four social fears. From the results it seems that while social phobics with three fears try to manage their problems by primary or informal care, those with four or more fears take mental health care. Whether there is a clear threshold between number of fears could be examined in future studies. Moreover, it seems as if having only one social fear has not much negative influence on quality of life, while with increasing number of social fears quality of life dramatically decreases. However, the explained variance by the number of fears is 38
relatively low. Thus, future studies are needed to examine the impact of the factors of social phobia also other than the number of social fears on quality of life.
From a public health perspective, we can suggest that mental health care givers should pay attention to the number of social fears in order to check the severity of social phobia. The information may be helpful to prepare the most appropriate treatment plans according to the severity of the social phobia. For instance, with comprehensive interventions that target the different domains of life, social phobics could learn to manage better with the difficulties at work, school or in other areas.
The present study should be considered in the light of several limitations. First, the results have been gathered from just one wave, so it is not possible to make causal relationships between the severity of the social phobia in terms of comorbidity, help-seeking behaviour, quality of life and the number of social fears. Second, our study assessed only six social fears. A broader range of social situations would make the current results more confident. Finally, comorbidity is limited to DSM-III-R Axis I disorders. Personality disorders, which might give a broader view about the respondents with social phobia, were not included.
Despite these limitations, however, this study has made it clear that the number of social fears is an important variable in determining the severity of social phobia. These results indicate that as the number of social fears increases social phobia becomes more severe and the burden of the disorder, in terms of comorbidity and quality of life, turn out to be heavier.
39
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Hankin, B.L., Fraley, R.C., Lahey, B.B., Waldman, I.D. (2005). Is depression best viewed as a continuum or discrete category? A taxometric analysis of childhood and adolescent depression in a population-based sample. Journal of Abnormal Psychology, 114(1), 96-110. Heimberg, R.G., Stein, M.B., Hiripi, E., Kessler, R.C. (2000). Trends in the prevalence of social phobia in the United States: a synthetic cohort analysis of changes over four decades. Eur Psychiatry, 15, 29-37. Kessler, R.C., Berglund, P., Demler, O., Jin, R., Merikangas, K.R., Walters, E.E. (2005). Lifetime Prevalence and Age-of-Onset Distributions of DSM-IV Disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry, 62, 593-768. Kessler, R.C., McGonagle, K.A., Zhao, S. et al. (1994). Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Arch General Psychiatry, 51, 8-19. Kessler, R.C., Stang, P., Wittchen, H.U., Stein, M., Walters, E.E. (1999). Lifetime comorbidities between social phobia and mood disorders in the US National Comorbidity Survey. Psychological Medicine, 29, 555-567. Kessler, R.C., Stein, M.B., Berglund, P. (1998). Social Phobia Subtypes in the National Comorbidity Survey. Am J Psychiatry, 155(5), 613-619. Kringlen, E., Torgersen, S., Cramer, V. (2006). Mental illness in a rural area: A Norwegian Psychiatric Epidemiological Study. Soc Psychiatry Psychiatr Epidemiol., 41, 713-719. Kringlen, E., Torgersen, S., Cramer, V. (2001) A Norwegian Psychiatric Epidemiological Study. Am J Psychiatry, 158(7 ), 1091-1098. Lepine, J.P., Lellouch, J. (1995). Classification and epidemiology of social phobia. Eur Arch Psychiatry Clin Neurosci, 244, 290-296. Magee, W.J., Eaton, W.W., Wittchen, H.U., McGonagle, K.A., Kessler, R.C. (1996) Agoraphobia, simple Phobia, and Social Phobia in the National Comorbidity Survey. Arch Gen Psychiatry, 53, 159-168. Offord, D.R., Boyle, M.H., Campbell, D. et al. (1996). One-Year Prevalence of Psychiatric Disorder in Ontarians 15 to 64 Years of Age. Can J Psychiatry, 41, 559-561. Patel, A., Knapp, M., Henderson, J., Baldwin, D. (2002). The economic consequences of social phobia. Journal of Affective Disorders, 68, 221-233. Robins, L.N., Wing, J., Wittchen, H.U. et al. (1988). The composite international Diagnostic Interview: an epidemiologic instrument suitable for use in conjuction with different diagnostic systems and in different cultures. Arch Gen Psychiatry, 45, 1069-1077. Safren, S.A., Heimberg, R.G., Brown, E.J., Holle, C. (1996). Quality of life in social phobia. Depression and Anxiety, 4, 126-133.
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Schneier, F.R., Johnson, J., Hornig, C.D., Liebowitz, M.R., Weissman, M.M. (1992). Social Phobia: Comorbidity and Morbidity in an Epidemiologic Sample. Arch Gen Psychiatry, 49, 282-288. Skodol, A.E., Oldham, J.M., Bender, D.S., Dyck, I.R., Stout, R.L., Morey, L.C., Shea, M.T., Zanarini, M.C., Sanislow, C.A., Grilo, L.M., McGlashan, T.H., Gunderson, J.G. (2005). Dimensional Representations of DSM-IV Personality Disorders: Relationships to Functional Impairment. Am JPsychiatry,162, 1919-1925. Smeets, R.M.W., Dingemans, P.M.A.J. (1993). Composite International Diagnostic Interview (CIDI), Version 1.1. World Health Organization, Amsterdam/Geneva. Spitzer, R.L., Williams, J.B.W., Gibbon, M., First, M.B. (1992). The Structured Clinical Interview for DSM-III-R (SCID) I: history, rationale, and description. Arch Gen Psychiatry, 49, 624-629. Stein, M.B., Deutsch, R. (2003). Brief Report: In search of social phobia subtypes: similarity of feared social situations. Depression and Anxiety, 17, 94-97. Stein, M.B., Kean, Y.M. (2000). Disability and quality of life in social phobia: Epidemiological findings. Am J Psychiatry, 157, 1606-1613. Stein, M.B., Torgrud, L.J., Walker, J.R. (2000). Social Phobia Symptoms, Subtypes, and Severity. Findings from a community survey. Arch Gen Psychiatry, 57, 1046-1052. Vriends, N., Becker, E.S., Meyer, A., Michael, T., Margraf, J. (2007). Subtypes of social phobia: Are they of any use? Journal of Anxiety Disorders, 21, 59-75. Ware, J.E., Sherbourne, C.D. (1992). The MOS 36 item short-form health survey (SF36): I. Conceptual framework and item selection. Medical Care, 30, 473-483. Ware, J.E., Snow, K.K., Kosinski, M., Gandek, B. (1993). SF-36 Health Survey, Manual & Interpretation Guide, The Health Institute, New England Medical Center Boston. Weissman, M.M., Bland, R.C., Canino, G.J., Greenwald, S., Lee, C.K., Newman, S.C., Rubio-Stipec, M., Wickramaratne, P.J. (1996). The cross-national epidemiology of social phobia: a preliminary report. International Clinical Psychopharmacology, 11(suppl 3), 9-14. Wittchen, H.U., Fuetsch, M., Sonntag, H., Muller, N., Liebowitz, M.R. (2000). Disability and quality of life in pure and comorbid social phobia. Findings from a controlled study. Eur Psychiatry, 15, 46-58. Wittchen, H.U., Robins, L.N., Cottler, L.B., Sartorius, N., Burke, J.D., Regier, D.A., and participants in the Multicentre WHO/ADAMHA Field Trials (1991). Cross-cultural feasibility, reliability and sources of variance in the CIDI. Br J Psychiatry, 159, 645-653. World Health Organization (1990). Composite International Diagnostic Interview (CIDI), Version 1.0. World Health Organization, Geneva.
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Chapter 3 Economic costs of social phobia: a population-based study
Abstract Background: Information about the economic costs of social phobia is scant. In this study, we examine the economic costs of social phobia and subthreshold social phobia. Methods: Data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS) which is a population-based prospective study (n = 4,789). Costs related to health service uptake, patients’ out-of-pocket expenses, and costs arising from production losses were calculated for the reference year 2003. The costs for people with social phobia were compared with the costs for people with no mental disorder. Results: The annual per capita total costs of social phobia were € 11,952 (95% CI = 7,748-16,156) which is significantly higher than the total costs for people with no mental disorder, € 2,957 (95% CI = 2,690-3,224). When adjusting for mental and somatic co-morbidity, the costs decreased to € 5,765 (95% CI = 2,314-9,216), or 277 million euro per year per 1 million inhabitants, which was still significantly higher than the costs for people with no mental disorder. The costs of subthreshold social phobia were also significantly higher than the costs for people without any mental disorder, at € 4,645 ( 95% CI = 2,517-6,773). Limitations: The costs presented here are conservative lower estimates because we only included costs related to mental health services. Conclusions: The economic costs associated with social phobia are substantial, and those of subthreshold social phobia approach those of the full-blown disorder.
This chapter has been published as: Acarturk, C; Smit, F.; de Graaf, R; van Straten, A; ten Have, M; Cuijpers, P (2008). Economic costs of social phobia: A population-based study. Journal of Affective Disorders, http://dx.doi.org/10.1016/j.jad.2008.10.008.
43
Introduction Social phobia is characterized by a persistent fear of negative evaluation or scrutiny by others in social or performance situations (APA, 1994). Population studies indicate that social phobia is one of the most prevalent psychiatric disorders (Kasper, 1998; Kessler et al., 1994; Furmark et al., 1999). It is associated with huge losses in quality of life (Wittchen, Fuetsch, Sonntag, Muller & Liebowitz, 2000; Acarturk, de Graaf, van Straten & Cuijpers, 2008), serious functional impairment in various domains of life (Schneier et al., 1994) and high levels of service use (Magee, Eaton, Wittchen, McGonagle & Kessler, 1996). This debilitating mental disorder is also associated with increased economic costs (Patel, Knapp, Henderson & Baldwin, 2002, Andlin-Sobocki, Bengt, Wittchen & Olesen, 2005). Previous research indicated that people with social phobia experience increased financial dependency (Schneier, Johnson, Hornig, Liebowitz & Weissman, 1992; Leon, Portera & Weissman, 1995), reduced work productivity (Kessler & Frank, 1997; Wittchen et al., 2000; Wittchen & Beloch, 1996), high levels of unemployment (Patel, et al., 2002; Wittchen et al., 1996), absenteeism from work (Lecrubier et al., 2000; Wittchen et al., 1996), and use of prescribed medication (Patel et al., 2002).
Despite these indications of the burden of social phobia, the economic cost of this disorder in the general population is less well studied (Patel et al., 2002; Löthgren, 2004; Greenberg, Sisitsky, Kessler, Finkelstein & Berndt, 1999; Smit et al., 2006; Konnopka, Leichsenring, Leibing & Köning, 2008). The only study that to our knowledge has specifically examined the economic costs of social phobia states that people with social phobia have significantly more GP contacts and they use significantly more prescribed oral medication compared to the not mentally disordered population (Patel et al., 2002). However, to understand the overall economic burden of social phobia, more research in this area is needed.
Social phobia often occurs together with other psychiatric disorders (Lecrubier et al, 2000). This co-morbidity leads to increased disability, lower quality of life (Wittchen et al., 2000) and higher economic costs (Patel et al., 2002). It is clear that if the costs of co-morbid disorders are included in calculating the burden of social phobia, that this burden will be overestimated. On the other hand, since co-morbidity is so common in social phobia, these extra costs cannot be ignored either (Greenberg et al., 1999). Therefore, it is important to take these co-morbid disorders into account when calculating costs for social phobia.
44
The present study firstly aims to examine whether social phobia is associated with significantly increased medical and non-medical costs compared to no mental disorder. This is performed in a large, representative, sample of the Dutch population. Secondly, we examine how the economic costs of social phobia are broken down according to the distinct types of social fears. Earlier research has documented that social fears other than the speaking fears are related to higher disease burden (Kessler, Stein & Berglund, 1998). However, no previous study has investigated the relationship between type of fear and economic costs. This touches on another issue. According to some research, social phobia lies on a continuum, and its disease burden is related to the number of social fears rather than to the distinct types of fear (Stein, Torgrud & Walker, 2000). Therefore, it is also interesting to study the relationship between the economic costs and the number of social fears. Finally, we examine the economic costs of subthreshold social phobia. Previous research indicated that the burden of the illness and the reduction in work productivity in subthreshold social phobia resemble those of fullblown social phobia (Wittchen et al., 2000). Highlighting the economic burden of subthreshold social phobia may underscore the importance of developing awareness, recognition and effective treatment of social phobia especially in its early phases.
Methods The present study is part of a series of studies on the costs of mental disorders with NEMESIS, beginning with the study of Smit et al. (2006) on the costs of common mental disorders and followed a study on the costs of minor depression (Cuijpers, Smit, Oostenbrink, de Graaf, ten Have & Beekman, 2007) and of panic disorder (Batelaan, Smit, Graaf, Balkom, Vollebergh & Beekman, 2007).
Subjects and procedure The data from the Netherlands Mental Health Survey and Incidence Study (NEMESIS) which have been described in detail elsewhere (Bijl, Ravelli & van Zessen, 1998a) were used to conduct the present cost-of-illness study. The sample was obtained by means of a multistage, stratified and random procedure in three steps (Bijl, van Zessen, Ravelli, de Rijk & Langendoen, 1998b). First, a sample was drawn of 90 Dutch municipalities stratified on the basis of urbanization and geographic distribution . Second, a sample of private households (addresses) from post office registers was obtained. The number of households selected in
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each municipality was determined by the size of its population. The third step was to choose which individuals to interview. The residents of the selected households were sent a letter of introduction signed by the Minister of Health requesting them to take part. One respondent with the most recent birthday was randomly selected in each household, on condition that s(he) was between 18 and 64 years of age and sufficiently fluent in Dutch to be interviewed. To schedule the appointments for the face-to-face interviews, the residents were contacted by telephone. Households with no telephone or with ex-directory numbers (18%) were visited in person. Eligible persons who were not immediately available were contacted later in the year. First the aims of the study were explained and then the participants provided informed consent. The study protocol was approved by an independent medical ethics committee.
In the first round of the data collection, from February through December 1996, a total of 7,076 persons were interviewed (response rate of 69.7%) (Bijl et al., 1998b). Refusal was the most important reason for non-response. Although males in the age group 18-24 years were slightly underrepresented, the sample reflected adequately the Dutch population in terms of gender, civil status and urbanization level (Bijl et al., 1998b). The data were collected by 90 experienced interviewers. All of the interviewers underwent a 3 day training course in recruiting respondents and computer assisted interviewing. After that, there was a 4 day training course focussing specifically on the content of NEMESIS and the use of CIDI at the WHO-CIDI training centre of the Academic Medical Centre in Amsterdam.
All participants in the first wave (T0) were approached for the follow-up (T1) 1 year (M = 379 days, SD = 35) after baseline. Of the 7,076 persons from T0, 5,618 (79.4%) could be reinterviewed at T1. The presence of a mental disorder at T0 slightly increased the probability of loss to follow-up between T0 and T1 (OR=1.20, CI=1.04-1.38) (De Graaf et al., 2000). Social phobia also somewhat increased the probability of loss to follow-up between T0 and T1 (OR=1.37, CI=1.07-1.75) (De Graaf et al., 2000). The present study is based on the T1 sample because medical consumption was measured at T1. We restricted our analyses to the index group of people presenting with social phobia and its co-morbidities (N=109) and a reference group of people not meeting the diagnostic criteria for any mental disorder (N= 4770).
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Measures Diagnoses of mental disorders The diagnoses were based on DSM-III-R Axis I (Robins, Wing & Wittchen, 1998). The Composite International Diagnostic Interview (CIDI, WHO, 1990) Dutch 1.1 computerised version was used to determine the diagnoses (ter Smitten, Smeets & van der Brink, 1998). The CIDI is a structured interview developed by the World Health Organization (Smeets & Dingemans, 1993; Wittchen et al., 1991) on the basis of Diagnostic Interview Schedule (DIS) and the Present State Examination (PSE). It was designed for use by trained interviewers who are not clinicians. The CIDI is now being used worldwide, and WHO field trials have documented acceptable reliability and validity for nearly all diagnoses (Robins et al., 1998, Wittchen et al., 1991, Spitzer, Williams, Gibbonm & Firstm, 1991) with the exception of acute psychotic presentations. Whenever psychotic symptoms were detected, subjects were re-interviewed by trained clinicians with the Structured Clinical Interview for DSM-III-R, an instrument that is reliable and valid for diagnosing schizophrenia (Spitzer et al., 1991).
Social Fears: The following six social fears based on the DSM-III-R were assessed at T1: speaking fears (public speaking, talking with others, and speaking in front of a small group) and performance fears (using public toilets, eating or drinking in public, and writing while someone watches).
Subthreshold Social Phobia: If the subjects had at least one of those six social fears but did not experience significant functional impairment required to meet the diagnostic criteria for social phobia, then they were deemed to be cases of subthreshold social phobia.
Chronic medical condition was assessed at T0 with a questionnaire listing 31 common illnesses such as diabetes mellitus, chronic obstructive lung disease, cardiac disease, arthritis of knee or hip and cancer, from the Health Survey of Statistics Netherlands (CBS, 1989).
Sociodemographic variables such as gender, age, level of education (low = 1, high = 0), urbanicity (rural = municipalities with fewer than 500 households per square kilometre; urban = larger municipalities) cohabitation status (living alone =1, other=0), employment status (unemployment =1, other=0), and being a single parent (1 = yes; 0 = no) were assessed at T0.
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Resource use and costing The full economic costs of health services were calculated for the reference year 2003 in euros (€) (Oostenbrink et al., 2004).The time frame of the current study is restricted to this single year, so we did not correct for inflation, nor did we offset costs. The following types of costs were examined.
Direct medical costs are the costs related to health service use in the mental healthcare sector in the Netherlands, including general practitioners, social work and physiotherapy. Information on the subjects’ use of health services was obtained by means of a questionnaire which was based on the Trimbos and Institute of Medical Technology Assessment Cost Questionnaire for Psychiatry (TICP-P) (van Roijen, 2002). Subjects register the number of GP visits, sessions with psychiatrists, hospital days, etc. In a next step, medical resource use was costed by multiplying the number of health service units (consultations, hospital days, etc.) by their full economic costs (Oostenbrink et al., 2004).
To these we added the costs of
pharmacological interventions, calculated as the cost per standard daily dose (obtained from Pharmaceutical Compass at http://www.fk.cvz.nl) multiplied by the number of prescription days, plus the pharmacist’s dispensing fees of € 6.45 per prescription.
Direct non-medical costs occur when patients travel to health service providers and pay for parking. In the Netherlands, the average travel distance between a random address and a GP’s practice is 1.8 km. Travel distances to other health services are also known (Oostenbrink et al., 2004). This information was combined with the data about actual health service uptake. Travel distances were valued at € 0.16 per km and 1 hour parking time was valued at € 2.50. To this we added the costs of the patients’ time spent in travel, waiting and treatment at € 8.30 per hour. We only focused on direct non-medical costs related to transportation, parking, time spent, waiting and in treatment and these costs did not include costs for supported housing, vocational rehabilitation, and other forms of psychiatric rehabilitation.
Indirect non-medical costs arise when production losses occur due to illness. Subjects were asked about the number of days spent in bed on account of illness. These days in bed were distributed proportionally over working days (resulting in production losses due to work loss days) and days off work (resulting in production losses in the domestic sphere). To value a lost day in a paid job we used the age and gender specific monetary counter-value of production losses that occur during absence from work (Koopmanschap et al., 1995). For 48
people too ill to perform domestic tasks, these costs were valued at the market price of domestic help at € 8.30 per hour. We did not include costs of early retirement and disability funds.
All cost calculations were conducted in accordance with the Dutch guideline for health economic evaluations (Oostenbrink et al., 2004), which closely resembles other international guidelines (Langley, 1996; Siegel et al., 1997; Torrance, 1996).
Analysis All analyses could be performed within the regression analysis framework. This approach also helped to take into account several data characteristics. Initial non-response and dropout were handled by using corrective weights. After weighting, the sample followed exactly the same multivariate distribution over age, gender, civil status and urbanization as the Dutch population according to Statistics Netherlands (www.cbs.nl). In order to account for the nonnormality of the cost data, we based sample errors, 95% confidence intervals (CIs) and Pvalues on 2,500 bootstrap replications, while in each bootstrap step we obtained robust sample errors using the first-order Taylor-series linearization method. The latter was performed to obtain correct 95% CIs and P-values under weighting. In short, we conducted a series of re-weighted, robust, and bootstrapped regression analyses to arrive at the distinct cost estimates of social phobia.
First, we conducted four separate regression analyses, where the dependent variable was either total costs, direct medical costs, direct non-medical costs, or indirect non-medical costs. These were regressed on the contrast of interest - the variable “presence of social phobia versus no mental disorder”. Second, we repeated the above analyses, but now we adjusted the costs of social phobia for the statistically significant co-morbid disorders and chronic medical conditions. Next, we examined whether the costs of social phobia were related to specific symptoms. To this end, we created a new variable indicating whether the subject with social phobia had the specific symptom or not. Then we entered both variables as predictors of total costs. We repeated this procedure for every symptom of social phobia.
We subsequently examined whether an increase in number of social fears in social phobia was related to an increase in costs. We created a count variable with the number of social fears (one, two, and three or more social fears). This variable was entered in the regression equation 49
as a predictor of total costs, direct medical costs, direct non-medical costs, and indirect medical costs.
Finally, to see how subthreshold social phobia was related to costs, another set of regression analyses was conducted. A variable indicating the presence of subthreshold social phobia was created and entered as a predictor of costs. Because the subthreshold sample was chosen from a sample without any mental disorder, we did not adjust the costs for other mental disorders but we adjusted them to somatic disorders. The analyses were conducted with Stata version 8.2/ (Stata Corp., 2003, College Station, TX, USA).
Results Demographics Of the present sample 109 had social phobia and 124 had subthreshold social phobia. The whole sample (N=4,879) can be described as follows. 53% were women with a mean age of 42 years (range 18-64). The levels of education was distributed as follows: elementary 6%, lower vocational 36%, secondary 28%, higher vocational and academic 30%.Of the sample, 73% were living with a partner, 82% living in urban and 69 % was employed. We refer to Table 1 for the demographics of the subsamples such as social phobia sample, no mental disorder sample and subthreshold social phobia sample.
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Table 1. Demographics of the sample and the subsamples All Sample
Social Phobia Sample
No Mental Disorder Sample
Sociodemographic and somatic factors
%
%
%
Gender
Female
53
65
53
54
Male
47
35
47
46
42.0
42.0
42.0
41.5
Elementary
6
13
6
11
Lower
36
55
36
39
Secondary
28
22
28
23
Higher
30
9
30
27
Urban
82
82
82
83
Rural
18
18
18
17
Age (mean)
Educational level
Urbanicity
Cohabitation
Employment
Number of Social Fears
Subthreshold Social Phobia
Alone
27
39
27
35
Not alone
73
61
73
65
No
31
49
31
60
Yes
69
51
69
40
0
95
-
97
-
1
3
31
2
75
2
1
35
1
19
3
1
34
0
6
Co-morbidity All the subjects in the social phobia sample had at least one co-morbid condition, mostly simple phobia (42.2%), followed by depressive disorder (35.7%), generalized anxiety disorder (15.6%), dysthymia (13.7%), panic disorder (22.9%), agoraphobia (12.8%), alcohol abuse (6.4%) and alcohol dependence (7.3%). Moreover, 73% had at least one of the 31 common somatic illnesses. In addition, 68.5% of the subthreshold social phobia sample and 60% of the no mental disorder sample had at least one somatic illness.
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Per capita costs of Social Phobia The total cost of social phobia, € 11,952 (SE = 2,145; 95% CI = 7,748-16,156)
is
significantly higher than the total cost for people with no mental disorder € 2,957 (SE = 136; 95% CI = 2,690-3,224). The annual per capita costs of € 11,952 can be divided into three categories. First,
direct medical costs, which are related to the health service uptake,
amounting to € 774 (SE = 224; 95% CI = 334-1,213) in the social phobia sample. Second, the direct non-medical costs: € 339 (SE = 79; 95% CI = 185-494). The highest costs in the social phobia sample are the indirect non-medical costs due to production losses, amounting to € 11,446 (SE = 2,012; 95% CI = 7,502-15,391) (not in the table).
However, when we adjusted the costs for co-morbidity and somatic illnesses, the total costs of social phobia dropped to € 5,765, and indirect non-medical costs dropped to € 5,331. Both of these costs were thus partly explained by co-morbid dysthymia, alcohol abuse and somatic disorders. On the other hand when we controlled for other mental disorders and somatic disorders, direct medical costs and direct non-medical costs lost their statistical significance. In other words, the direct medical and non-medical costs of social phobia could be completely explained by the presence of co-morbid depression and simple phobia (Table 2).
We used the per capita costs to calculate the costs per 1 million inhabitants aged 18-65 years. This includes all cost categories (health service uptake, out-of-pocket expenses, production losses; and is equivalent to the per capita excess costs × prevalence × 1 000 000). With a prevalence rate of 4.8% (Bijl et al., 1998a), the unadjusted costs of social phobia was 574 million euro per year but become 277 million euro when adjusted for co-morbid mental and somatic illnesses.
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Somatic Disorders 2908 (248**, 2422 - 3394) Base Rate 1207 (130**, 952 - 1462) - 5 (20, - 44 – 34) 42 (19*, 4 – 79)
403 (162*, 85-721)
7 (22, -35-49) 1186 (533*, 141-2231) 983 (464*, 74-1892) 46 (19, 8-84)
Direct Medical -122 (186, -486-241)
(Robust) sample errors and 95% confidence intervals are based on 2500 bootstraps. * p< 0.05; ** p
