Vol. 16: e??-e??, September 2011
ORIGINAL RESEARCH PAPER
The relationship between alexithymia and maladaptive perfectionism in eating disorders: A mediation moderation analysis methodology S. Marsero1,2,3, G.M. Ruggiero1,2, S. Scarone3, S. Bertelli3, and S. Sassaroli1,2 1“Studi Cognitivi”, Post-graduate Cognitive Psychotherapy School, 2“Psicoterapia Cognitiva e Ricerca”, Post-graduate Cognitive Psychotherapy School, 3Eating Disorders Unit, Ospedale San Paolo, Milano, Italy
ABSTRACT. OBJECTIVE: This work aimed to explore the relationship between alexithymia and maladaptive perfectionism in the psychological process leading to eating disorders (ED). METHOD: Forty-nine individuals with ED and 49 controls completed the Concern over Mistakes subscale of the Frost Multidimensional Perfectionism Scale, the Perfectionism subscale of the Eating Disorders Inventory, the total score of the Toronto Alexithymia Scale, and the Drive for Thinness, Bulimia, and Body Dissatisfaction subscales of the Eating Disorders Inventory. We tested a model in which alexythimia is the independent variable and perfectionism is the possible mediator or moderator. RESULTS: Analyses confirmed the assumed model. In addition, it emerged that perfectionism played a mediating or moderating role when measured by different instruments. This result suggested that different instruments measured subtly different aspects of the same construct. DISCUSSION: Results could suggest that alexithymia is a predisposing factor for perfectionism, which in turn may lead to the development of eating disorders. (Eating Weight Disord. 16: e??-e??, 2011). ©2011, Editrice Kurtis
INTRODUCTION
Key words: Alexithymia, perfectionism, eating disorders, anorexia, bulimia, body dissatisfaction, drive for thinness. Correspondence to: Sara Marsero, CPSE, C.so Brunelleschi 91/d, 10141, Torino, Italy. E-mail:
[email protected] Received: March 19, 2010 Accepted: February 1, 2011
The term ‘alexithymia’ (literally ‘no words for feelings’) was coined by Sifneos (1) to describe a cluster of cognitive and affective characteristics in patients with psychosomatic diseases. It has undergone theoretical refinement in the last few years and has evolved into a construct that includes four characteristics: (a) difficulty identifying feelings and distinguishing between feelings and the bodily sensations of emotional arousal; (b) difficulty describing feelings to other people; (c) constricted imaginal processes, as evidenced by a paucity of fantasies; (d) a stimulus-bound, externally-oriented cognitive style (2). In short, alexithymic patients have affective dysregulation and inability to self-soothe and to manage emotions because of a lack of awareness of emotions (3). An inability to modulate emotions could explain why some alexithymics are prone to discharge tension arising from unpleasant emotional states through impulsive acts or compulsive behaviours such as the self-starvation of anorexia nervosa (2).
There is evidence that eating disorder (ED) patients are more alexithymic than control samples (4, 5). Several studies have reported high levels of alexithymia in patients with ED (6-9). Thus, alexithymia may increase the probability of developing an ED (5, 6, 8, 10) and usually indicates severe EDs (11, 12). Furthermore, alexithymic subjects show more body checking behaviour and more body dissatisfaction than non-alexithymic subjects, as well as more social anxiety and lower self-esteem (13). Although alexithymia seems to be relevant to the mechanism underlying ED, it is, however, not considered to be the core psychopathological process. In fact, scientific literature considers perfectionism the most important psychological factor in terms of ED (14-16). Perfectionism generates an intensely self-critical attitude: errors, small or large, lead to the same degree of unbearable self-criticism in individuals with ED (17, 18). Perfectionism is a salient trait in women with ED during acute illness (16, 19) and after recovery (20, 21), and represents a risk factor for anorexia nervosa (14). Therefore many studies have confirmed that pere1
S. Marsero, G.M. Ruggiero, S. Scarone, et al.
fectionism, in concert with low self-esteem or body dissatisfaction (21, 22), is a risk factor for ED (16, 23-27). In scientific literature, only three studies explored the relationship between alexythimia and perfectionism and they drew different conclusions. Laquatra and Clopton (28), and Taylor et al. (8) found that perfectionism and alexythimia do not correlate with each other. They both used the perfectionism subscale of Eating Disorders Inventory (EDI) (29), which is, however, actually not a gold standard for measuring the construct of perfectionism. Instead, Lundh et al. (30) used the total score of the Frost Multidimensional Perfectionism Scale (FMPS) (31) and the Positive and Negative Perfectionism Scale (PANPS) (32) and found that alexithymia significantly correlated with this measure. In sum, the literature suggests that not only perfectionism plays a key role in the psychopathology of ED but that alexithymia is also a relevant factor. Given that the scientific literature found inconsistent results when exploring the relationship between alexythimia and perfectionism using different measures of perfectionism, we decided to explore the nature of the correlation of the two above-mentioned factors in ED using two instruments: the perfectionism subscale of the EDI and the FMPS. The difficulty in decoding emotional states of alexithymic subjects could drive people to elaborate relational strategies primarily focused on performance and perfection. In turn, individuals with ED tend to narrow their perfectionism to adherence to unrealistic standards of controlled eating, low body weight and thin shape (15, 33). Thus, in this study we tested a model in which alexithymia is a predisposing factor for ED and perfectionism is a cognitive strategy intended to manage the emotional problems generated by alexythimia.
MATERIALS AND METHODS All participants were informed about the procedures and aims of the study and knew that the results of their assessments would be discussed during the initial sessions of the treatment. Each participant provided written consent. The Comitato Etico (Ethical Committee) of the ‘Studi Cognitivi’ Cognitive Psychotherapy School of Milan and the San Paolo Hospital of Milan approved the study. Participants Forty-nine Italian individuals with ED participated in the study (47 females, 2 males, mean age 32.36±14.89 yrs). We classified the particie2
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pants as individuals with anorexia nervosa (N=13), bulimia nervosa (N=12), or an eating disorder not otherwise specified (N=24) with the Structured Clinical Interview for DSM-IV axis I (SCID-I) (34, 35). Participants with ED were recruited from a population that was undergoing psychiatric and cognitive psychotherapeutic treatment for ED administered in the Eating Disorders Unit of the San Paolo Hospital of Milan, Italy. Participants were recruited during the initial assessment phase of treatment. Fortytwo of the participants with ED were high school graduates and seven were university graduates. Eight were married. All participants were either students or employed full- or parttime during the six months prior to the study. Psychologists trained in cognitive therapy (four years' training, according to the criteria of the Italian Ministero dell’Istruzione, dell’Università e della Ricerca) assessed demographic data and past or current psychological and/or psychopharmacological treatments. The psychologists administered the Italian version of SCID-I and a battery of self-report questionnaires. Criteria for inclusion in the study were a DSM diagnosis of anorexia, bulimia, or EDNOS based on SCID-I for the ED group, no DSM diagnosis of an anxiety or mood disorder or ED for the control group, a minimum age of 18 years, and the ability to comprehend written Italian. Forty-nine Italian individuals without ED were recruited as controls. They were matched for gender distribution, age range, level of education, marital status, and employment. Anagraphic data, height, and weight were collected on a paper questionnaire. The control group was tested with SCID-I to exclude the presence of ED. Individuals in the control group were not remunerated for their participation. None of them were being treated for either an emotional or a psychiatric disorder. Instruments The Italian version of SCID-I is a structured interview based on DSM criteria for diagnosis of axis I psychiatric disorders. We used the SCID-I for assessment of ED diagnosis in the clinical sample. We chose the drive for thinness, bulimia, body dissatisfaction, and perfectionism subscales of the Eating Disorders Inventory version 3 (EDI-3) (29) to measure ED. Drive for thinness, in particular, assesses a cardinal feature of ED, and is useful for screening for ED (29, 36-38). According to Garner (29, 38), the drive for thinness subscale assesses excessive concern with dieting, preoccupation with weight, and fear of weight gain. Polivy and Herman (39) found that high drive for thinness scores for college
Alexithymia in eating disorders
women reflected a preoccupation with weight that was as severe as that for individuals with ED. Drive for thinness derives from the clinical conceptualizations of Hilde Bruch (40, 41) and Gerald Russell (42). We used the Italian official translation of EDI-3 published by Organizzazioni Speciali Firenze (43). The Toronto Alexithymia Scale (TAS 20) (44) measures three aspects of the alexithymia construct: difficulty identifying feelings, difficulty describing feelings, and an externally-oriented way of thinking. This is a 20-item self-report questionnaire measuring the ability to identify one’s emotions and the degree to which the respondent exhibits a concrete, externally-oriented style of thinking. The TAS item scores lie on a five-point Likert scale, and the total score ranges from 20 to 100. Bressi et al. have validated the Italian version of TAS (45). Frost et al.’s Multidimensional Perfectionism Scale (FMPS) (31) is a 35-item self-report questionnaire based on theories of perfectionism. In this study we used the Concern over Mistakes subscale, which measures maladaptive perfectionism. Psychometric studies show that the FMPS and the subscale Concern over Mistakes have adequate reliability (Cronbach’s alphas greater than 0.7) (31, 46). Actually, the best measure of perfectionism is the Concern over Mistakes subscale of the FMPS, which appears to be the central feature of perfectionism (18, 47). Concern over Mistakes has been found to correlate with measures of psychopathology among non-clinical populations (see 47 for a review) and to be significantly higher among clinical populations including most anxiety disorders, depression, and eating disorders (see 47, 48 for reviews). G.M.R. translated the FMPS into Italian. The Italian versions of the scales and the questionnaires were then back-translated into English by a native English speaker who was not familiar with the questionnaire. One of the authors of the FMPS compared the original version and the re-translated version of the FMPS and did not note any meaningful differences (Randy Frost, 29 December 2004, e-mail communication). The English and Italian translations of the FMPS were reviewed and approved by an English language teacher (Romano Denaro, 23 June 2004, oral communication). Reliability based on internal consistency was confirmed with a Cronbach’s alpha coefficient >0.7 for each instrument and each sample (0.85 for drive for thinness of the EDI in the clinical sample; 0.87 for drive for thinness of the EDI in the non-clinical sample; 0.71 for bulimia of the EDI in the clinical sample; 0.73 for bulimia of the EDI in the non-clinical sample; 0.83 for body dis-
satisfaction of the EDI in the clinical sample; 0.84 for body dissatisfaction of the EDI in the nonclinical sample; 0.73 for perfectionism of the EDI in the clinical sample; 0.74 for perfectionism of the EDI in the non-clinical sample; 0.81 for concern over mistakes of the FMPS in the clinical sample; 0.88 for concern over mistakes of the FMPS in the non-clinical sample; 0.80 for the TAS in both the clinical and non-clinical samples). Statistical procedures The work tested a mediating/moderating model in which alexithymia was the initial variable; perfectionism could also play a role (as either mediator or moderator), being used by the patient to manage his or her difficulty in decoding emotions focusing on a high standard of perfection in various domains; the final narrowing of this perfectionism to the domain of eating, weight, and food would produce the dependent variable, the symptoms of ED. Regarding the exact role played by perfectionism in the model, it would be wrong to say that there were strong reasons supporting the prediction that perfectionism was a mediating or moderating variable, but careful scrutiny of the non-statistical implication of concepts of mediation and moderation provides some suggestions for a hypothesis. In fact, a mediator would be a variable deeply embedded within a process (in this case, a psychological process), given that a mediator both influences the dependent variable and is influenced by the independent variable. Thus, the mediator seems to measure changing thoughts belonging to a mechanism which is a chain of cognitive beliefs. On the other hand, a moderator operates outside the relationship between independent and dependent variables. A moderator influences a mechanism but it is not influenced by the mechanism; it is a contextual factor which influences a relationship but is not influenced by a relationship between independent and dependent variables (49). From this perspective, given that perfectionism is a cognitive belief, it seems to be a better candidate for the role of mediation. In order to test mediation and moderation effects, we used multiple regression linear analysis (50, 51). Mediation was tested following the four regression steps recommended by Baron and Kenny (52): [1] measuring the effect of the independent variable on the dependent variable; [2] measuring the effect of the independent variable on the mediator; [3] measuring the effect of the mediator on the dependent variable; [4] measuring the effect of the independent variable on the dependent variable controlling for the mediator. Complete mediation is given by significant results for [1], [2], Eating Weight Disord., Vol. 16: N. 3 - 2011
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and [3] and non-significant results for [4], whereas a significant result for [4] means that the mediation is partial. We measured main effects in order to observe the effects of individual cognitive variables on measures of ED (53) and interactive effects in order to obtain an approximated measure of moderation effects (although some have stricter criteria for moderation effects than for interactions) (54). We used centred predictor values in order to reduce multicollinearity (50, pp. 28-35). We chose to include both the clinical and the non-clinical group in all regression analyses. We combined data from clinical and nonclinical individuals so that we could examine the interactive effects at each level of the entire range of values for Concern over Mistakes, Perception of Control, and Self-esteem, not only in terms of high and low values but also in terms of values for clinical or non-clinical populations. A potential problem with combining the two groups is that the scores of the dependent variables will not be normally distributed. To implement a regression analysis, however, it is sufficient that residuals are normally distributed (51, pp. 137-141). All of the tests gave evidence that the distribution of residuals met the requirements for normality (Kolmogorov-Smirnov, Shapiro-Wilk, Normal Q-Q plot, Detrended Normal Q-Q plot). Neither the histogram nor the probability-probability plot indicated that the assumption of normality of residuals was violated.
Alexithymia (Independent variable)
c
Drive for thinness (Dependent variable)
Concern over mistakes (Mediator variable) a
b
Alexithymia (Independent variable)
c’
Drive for thinness (Dependent variable)
a path (direct effect of independent on mediator): coeff.=4.42; S.E.=0.63; t=7.04; p
