The Persistence of Depressive Symptomatology among ... - NCBI

The Persistence of Depressive Symptomatology among Prepaid Group Practice Enrollees: An Exploratory Study JANET R. HANKIN, PHD,

AND

BEN Z. LOCKE, MS

Abstract: This exploratory study examines the persistence of depressive symptomatology as measured by the Center for Epidemiologic Studies Depression Scale (CES-D). Over a 12-month period, half of a group of 309 prepaid group practice enrollees reporting depressive symptoms at the beginning of the interval also had high scores on the CES-D at the end of the interval. Sociodemographic characteristics did not

predict persistence of depression. Persistence of depression was positively associated with initially reporting cognitive and affective types of depressive symptoms, the presence of physical illness, the seeking of psychiatric treatment, and the receipt of psychotropic drug prescriptions. (Am J Public Health 1982; 72:1000-1007.)

A growing number of researchers have documented that a significant number of primary care patients suffer from mental disorder and emotional problems. '2 However, little is known concerning the persistence of emotional problems in this particular patient population. Three follow-up studies of general practice patients have been conducted in the British National Health Service. The authors report that 27 per cent to 73 per cent of general practice patients suffer from persistent mental disorder. The wide range in these rates reflect differences in the setting, the method of case identification, and the length of follow-up interval.-I5 The present study focuses on depressive symptomatology, as measured by a self-administered questionnaire, among primary care patients. Over a 12-month period, what proportion of patients scoring high on a depression inventory at the beginning of the interval also have high scores at the end of the study period? What are the differences between individuals reporting depressive symptoms at both the beginning and the end of the time period and persons who report the symptoms only at the beginning of the period? Depressive symptomatology represents an emotional symptom which is commonly somatized by primary care patients. Patients suffering from depression often present symptoms of fatigue, backache, and appetite disturbance. Depressive symptoms may co-occur with certain physical illnesses and may be a response to experiencing a chronic disease.-9

ogy Scale (CES-D) was used. The CES-D is a self-administered questionnaire consisting of 20 items chosen from previously developed scales, including those of Zung, Beck, Raskin, Gardner, and the MMPI. The range of possible scores on the CES-D is 0 through 60. The cut-off for depressive symptomatology is a score of 16 or more.* The scale has been psychometrically evaluated, clinically validated, and used in three large community studies.'0'5 The CES-D does not discriminate between subtypes of depression nor distinguish between primary and secondary depression. "The population with scores of 16 and above contains a high proportion of individuals with major depressive disorder and dysthymia (DSM III diagnoses), as well as some persons who suffer from severe symptoms of clinical depression but do not meet the (DSM III) criteria for diagnosis."25 Several validity studies of the CES-D have been conducted. Myers and Weissman compared CES-D scores to diagnoses based on Research Diagnostic Criteria and found a false negative rate of 36.4 per cent and a false positive rate of 6.1 per cent.'6 In another study, Weissman and her colleagues compared results from the Raskin Rating Scale, which was completed by specially trained social workers, to CES-D scores for 148 acutely depressed psychiatric outpatients. The sensitivity was 99 per cent. The acutely depressed patients also completed the Symptom Checklist 90 (SCL-90). The correlation between the CES-D score and the score on the SCL-90 depression factor was .73." Husaini, et al, report that the CES-D is able to distinguish between patients and nonpatients, among various psychiatric diagnostic groups, and among depressed patients with different levels of problem severity.'2 While the CES-D is not designed to substitute for a psychiatrist's interview, it is a useful and inexpensive tool for screening large populations for the presence of depressive symptomatology.'2-'4 In a national sample for the Health and Nutrition Examination Survey, 17 per cent of the adults aged 25 and

Method and Materials In this study, the National Institute of Mental Health's Center for Epidemiologic Studies Depressive SymptomatolAddress reprint requests to Janet R. Hankin, PhD, Center for Metropolitan Planning and Research, Shriver Hall, Johns Hopkins University, Baltimore, MD 21218. Mr. Locke is with the National

Institute of Mental Health. This paper, submitted to the Journal March 4, 1981, was revised and accepted for publication March 19, 1982. Editor's Note: See also related editorial p 982 this issue. © 1982 American Journal of Public Health 1 000

*The questionnaire is shown as part of Table 4.

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PERSISTENCE OF DEPRESSION

over scored 16 or higher on the CES-D.'7 The CES-D has been used in one study of the persistence of depressive symptoms in a community sample. Hornstra and Klassen found that 42 per cent of persons in their sample from Kansas City, Missouri had CES-D scores of 16 and above at both the beginning and the end of their 12-month study period.'8 Research Site The research was conducted at the Columbia Medical Plan (CMP), a prepaid group practice located in Columbia, Maryland, a new town of about 50,000 population located between Washington, DC and Baltimore, Maryland. The CMP enrollment at the time of the study was approximately 21,000. While precise data on the penetration rates are not available, the general evidence is that between 35 per cent and 40 per cent of Columbia residents join CMP. CMP offers comprehensive prepaid medical coverage to its enrollees. About 20 per cent of all visits are provided on a fee-for-service basis. The current study, however, is restricted to prepaid practice enrollees. The prepaid medical coverage includes preventive health services, diagnostic services, treatment, hospitalization, follow-up care, etc. The Plan is divided into five specialty departments: Internal Medicine, Obstetrics-Gynecology, Pediatrics, Surgery, and Psychiatry. At the time of the study, an Urgent Care Department offered walk-in care 24 hours a day, seven days a week. Copayment for nonpsychiatric visits is $2 per visit. CMP represents an integrated health/mental health delivery care site. Enrollees may receive short-term psychotherapy from the Department of Psychiatry, which does not set a limit on the number of psychiatric visits. The copayment for family, couple, and individual sessions is $10; group therapy costs $7.50. Thirty days of psychiatric hospitalization are included in the benefit package. A referral is not required to initiate psychiatric care, and nearly three-fourths of all adult psychiatric patients are self-referred. A total of 22 per cent of all adults continuously enrolled in CMP from 1973-1975 visited the Department of Psychiatry at least once during that time period. Among enrollees of all ages, less than 15 per cent of all persons with a' diagnosed mental disorder in 1975 failed to seek care in the Department of

completed the CES-D. Twenty-one per cent (414) scored 16 or above on the CES-D. A follow-up study was conducted on a subgroup of persons completing the CES-D in 1977-1978. A random sample of 700 persons scoring below 16 initially and all persons with CES-D scores of 16 and above initially were mailed a copy of their CES-D on their one-year anniversary date. This paper focuses exclusively on the 414 persons who scored 16 or above on the initial CES-D. Each patient was mailed two reminders. A telephone call was then made and the respondent was asked to return the questionnaire. The response rate for the initially depressed group was 75 per cent, yielding 309 respondents. Budgeting considerations limited the conversion of refusals to three attempts per respondent. The respondents and nonrespondents were very similar on their initial CES-D scores; the median for each group was 22. However, there were some significant sociodemographic differences between the two groups. Nonrespondents were more likely to be 18-24 years old or over 44 years old, nonWhite, and not married. These biases must be considered in interpreting the results.

Results

Psychiatry.

Among patients scoring 16 and above on the initial CESD who responded to the follow-up query, half were depressed according to the CES-D one year later (n = 155). These results parallel Hornstra and Klassen's persistence rate of 42 per cent.'8 It is important to emphasize that patients who scored 16 or above on the CES-D at two points in time one year apart may have scored below 16 at some point during the intervening year. In addition, patients scoring high on the CES-D at follow-up may be experiencing the same episode of depressive symptoms, or a new episode of depressive symptoms. The current study was not designed to address these two issues. Several factors relating to the persistence of depressive symptomatology were studied, including severity of depression as measured initially. sociodemographic characteristics, physical illnesses experienced and visits to CMP, type of depressive symptoms reported, and type of treatment received.

Study Design A consecutive series of adult prepaid group practice enrollees seen in the Departments of Internal Medicine and Obstetrics-Gynecology completed the CES-D before they consulted with their internist, obstetrician-gynecologist, or nurse practitioner. The study was conducted during four two-week periods in December of 1977 and in March, May, and July of 1978 in order to account for seasonal variation. At the time of the CES-D administration, the patient also provided information on sociodemographic characteristics. Data on diagnoses, visits, and prescriptions filled were obtained from the encounter information system of CMP for a 27-month interval centered around the initial administration of the CES-D. A total of 1,937 patients (78 per cent)

Initial CES-D Score Table 1 shows that the severity of symptoms measured initially is positively related to the follow-up CES-D score. The higher the initial score, the greater the probability of the persistence of depressive symptoms. Patients whose symptoms persist score nearly three points higher, on the average. on the initial CES-D than patients whose symptoms remit. Given the large difference in variances between the two groups, t-tests were not computed. An examination of the distribution of the change in CES-D scores from the initial administration to the follow-up reveals that 39 per cent of all respondents lowered their follow-up CES-D score by 10 or more points.

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HANKIN AND LOCKE

sociodemographic correlates of persistent depression as measured by the CES-D.'8 Table 2 shows results which support their findings for persistence of CES-D scores. While race is significantly related to persistent depression, its effect becomes insignificant when other sociodemographic factors are controlled.** Experience of Physical Disease and Visits to CMP Other researchers have shown that depressive symptoms may co-occur with or be a result of experiencing a physical illness. Table 3 illustrates the type of illnesses diagnosed for the two groups of patients during a 27-month interval centered around the initial administration of the CES-D. Patients are counted only once within a diagnostic category, regardless of the number of visits they make for a disease. Patients may have received several types of diagnoses within an ICDA category during the study period, but

TABLE 1-Persistence and CES-D Scores Per Cent with Follow-up CES-D 15 or Less by Initial CES-D Scores Per Cent with Follow-up CES-D 15 or less Persistence Remission Total Initial CES-D

16-24

77

24 Total

78 155

::-

105

49 154 X2= 10.93 p < .01

182

58%

127 309

39% 50%

Comparison of Initial and Follow-up CES-D Scores for Patients with Persistence and Remission Follow-up CES-D Initial CES-D

Persistence Remission

Mean

Standard Deviation

Mean

Standard Deviation

N

25.20 22.54

7.33 6.84

27.90 8.54

8.88 4.29

155 154

**Two methodological problems may account for the results from the CMP study. Age, race, and marital status are significantly different for the responders and nonresponders to the survey. In addition, some of the characteristics, which were measured only initially, may have changed during the one-year period. It is conceivable that respondents may have changed jobs, completed education, or changed marital status during the year in question. On the other hand, sex and race remain constant, while age increases exactly one year for the entire sample.

Sociodemographic Characteristics While previous research has indicated a relationship between sociodemographic characteristics and the prevalence of depression,'9-22 Hornstra and Klassen found no

TABLE 2-Comparison of Soclodemographic Characteristics of Patients with Persistence and

Remission Persistence

Sociodemographic Characteristicst

Sex Male Female Age 18-24 25-44 45+ Race White NonWhite Education Less than bachelor's degree Bachelor's degree or more Employed Yes No

Occupation Executives, Managers Administrators, clerks, manual labor Marital Status Not married Married Total

Total

Remission

N

%

N

%

N

27 128

47.4 50.8

30 124

52.6 49.2

57 252

26 92 33

52.0 48.2 54.1

24 99 28

48.0 51.8 45.9

50 191 61

127 27

48.1 65.9

137 14

51.9 34.1*

264 41

87

50.9

84

49.1

171

62

47.0

70

53.0

132

104 50

50.5 49.0

102 52

49.5 51.0

206 102

48

49.5

49

50.5

97

55

50.9

53

49.1

108

48 105 155

47.5 51.5 50.2

53 99 154

52.5 48.5 49.8

101 204

309**

$Measured at the time of initial visit. *Chi square significant at p < .05 "Totals within categories may vary due to missing values.

1 002

AJPH September 1982, Vol. 72, No. 9

PERSISTENCE OF DEPRESSION TABLE 3-Proportion Receiving a Diagnosis in Each Category during 27-Month Period Depresson Status at Follow-Up Illness Category

Infective and Parasitic Neoplasms Endocrine, Nutrition, Metabolic Blood and Blood Forming Organs Mental Disorders Nervous System and Sense Organs Circulatory System Respiratory System Digestive System Genitourinary System Complications of Pregnancy Skin and Subcutaneous Tissue Musculoskeletal and

Persistence

Remission

A C

.53 .19

.44 .13

C

.14

.14

A/C A/C

.36

.22t

M C A C M

.48 .22 .53 .15 .41

.19 .55 .09 .45

M

.50

.35t

C C A A A A

.25

.19

.46

.41

.96 .80 .26

.94 .73 .26

Connective Congenital Anomalies Injury Other Accidents Well Care Symptoms Procedures

.37t

A

N

155

154

A = acute, C = chronic, A/C = acute/chronic, M = mixed NOTE: Patients were counted only once within each category regardless of the number of visits for that condition. Patients could receive a diagnosis in more than one category. *When the proportion of persons receiving the diagnosis was low (less than .10 for both groups), the proportion is not shown because of large sampling variability. tp < .05

are still counted only once in that category. Patients are duplicated across categories.

Three board-certified internists developed the classification scheme for diagnoses received at CMP. Acute conditions were defined as lasting less than three months, chronic conditions as persisting more than three months, and acute/ chronic conditions as representing chronic conditions with acute manifestations. Each ICDA category was examined to ascertain whether acute, chronic, or acute/chronic conditions predominated in that category. The distribution of diagnoses within each ICDA category in 1978 for the entire CMP enrolled population was analyzed. This scheme classified infective and parasitic diseases as predominately acute, neoplasms as chronic, etc., (Table 3). When acute, chronic, or acute/chronic conditions did not predominate, the category was classified as mixed (Nervous System and sense organs, Genitourinary system, Skin and subcutaneous tissue). Few of the differences between the two groups are statistically significant. For all but one acute illness category (Diseases of the Respiratory System), a higher proportion of persons depressed at follow-up receive that diagnosis compared to patients in remission. Patients depressed at followup show a statistically significant higher diagnosed prevalence of chronic physical disease: 78 per cent of the patients AJPH September 1982, Vol. 72, No. 9

with persistence versus 68 per cent of the patients with remission received at least one diagnosis for a chronic physical disease during the 27 months. Statistically significant differences appear for ICDA categories of Nervous system and sense organs and Skin and subcutaneous tissue. Patients with persisting depression visited the plan more often than patients with remitting depression. During the 27month period, patients depressed at follow-up averaged 22 visits to the plan, compared to 18 visits for persons with remitting depression. The utilization level for these two groups is higher than the mean for other CMP adult enrollees who averaged 16 plan visits during the 27-month period.t The picture that emerges is that the individuals whose symptoms persist visit the plan more frequently and experience more diagnosed physical illnesses than the patients whose symptoms remit. Type of Depressive Symptoms Reported Do the two groups of patients differ in the type of depression they report? Beck has identified four dimensions tlf one excludes visits to mental health specialists, the comparable means become: 19 visits for patients depressed at follow-up, 17 visits for patients with remitting depression, and 15 visits for other CMP adults. 1 003

HANKIN AND LOCKE

TABLE 4-Comparison of Responses for Patients with Persistence and Remission on Initial CES-D Rarely or None of the Time (Less than 1 Day) Percent with each response DURING THE PAST WEEK:

1. 2. *3. 4. 5. *6. 7. *8. *9. 10. 11. 12. 13. *14. *15. *16. 17. 18. *19. 20.

Occasionally Some or a or a Moderate Little of the Amount of Most or All of Time Time the Time (1-2 Days) (3-4 Days) (5-7 Days)

Persist Remit Persist Remit Persist Remit Persist Remit

was bothered by things that usually don't bother me ........................ did not feel like eating; my appetite was poor .............................. felt that could not shake off the blues even with help from my family or friends ... I felt that was just as good as other people ............. ................... had trouble keeping my mind on what was doing ......................... Ifelt depressed ........... ............................... felt everything did was an effort ......................................... felt hopeful about the future .......................................... I thought my life had been a failure ........................................ felt fearful .......................................... My sleep was restless .......................................... I was happy .......................................... talked less than usual . .......................................... felt lonely ..........................................

(C) 20 (S) 47 (A) 16 (C) 9

(C) 11 (A) (S)

5 9 (C) 14 (C) 51 (A) 31

(S) 23 (A) 13 (B) 25

People were unfriendly ..........................................

(A) 16 (C) 57

I enjoyed life .......................................... I had crying spells ............ .............................. l felt sad .......................................... felt that people disliked me .......................................... Icould not get "going" ...........................................

(A) 11 (B) 52 (A) 14 (C) 51 (S) 16

19 46 31 12 14 11 12 10 67 35 20 10 23 40 68 13 52 19 64 12

34 27 40 27 35 35 33 38 29 30 22 42 37 31 30 40 21 42 28 30

33 28 41 16 37 38 35 24 21 39 27 34 36 33 22 27 31 56 28 32

35 16 30 27 42 40 39 32 15 28 32 39 29 36 11 40 24 35 16 36

31 16 20 31 41 34 40 33 36 7 15 30 49 32 16 8 43 10 16 5 36

11 9 14 37 12 21 19 16 5 11 23 6 9 18 2 10 3 9 5 18

18 11 8 15 10 20 29 5 11 23 7 9 11 2 18 7 9 3 20

Patients were instructed to "Circle the number for each statement which best describes how often you felt or behaved this way-DURING THE PAST WEEK" *p