Somatic Complaints and the CES-D George A. Foelker, Jr., PhD* and Richard M. Shewchuk, PhDt Objective:To evaluate the Center for Epidemiology SurveysDepression (CES-D) scale for inordinate false positives, due to measurement of non-depression-related somatic complaints. Design: Cross-sectional correlation of analysis of random multi-cluster samples. Setting: Thirteen counties considered representative of the community-dwelling elderly population of Alabama. Participants: One-thousand-sixty persons aged 55 and older. Intervention: None. Main Outcome Measures: Study evaluated the relationship of somatic symptomatology, as measured by the Multi-Level Assessment Instrument's Physical Health Domain Index (PHDI) composite score and its three component indices, with the CES-D and its four component scales, particularly the Somatic scale.

Results: The CES-D total score and the Somatic scale were not related to: age increases in the sample; PHDI composite score or the three index scores; or to subgroups of high and low PHDI composite scores. Among those screened as depressed, the PHDI and the three indices were not related to the CES-D total score or three of the four subscales. The CES-D Somatic scale was positively related to those depressed persons with the highest number of total PHDI somatic complaints. However, among the depressed group there were more persons scoring greater than 1.5 standard deviations above the mean on the CES-D Depressive Affect scale (n = 81) than on the Somatic scale (n = 65). Conclusions:The CES-D and its Somatic scale were relatively unbiased by the respondent's somatic complaints. The CESD can continue to be considered valid under these circumstances. J Am Geriatr SOC40259-262,1992

epression is a common mental health problem among elderly persons. The NIMH epidemiological catchment area survey estimated that about 5% of community-dwelling elderly persons (age 65+) were diagnosed as depressed or dysthymic using the DSM-I11 criteria.', Different diagnostic procedures produce different estimates of the prevalence of depression among elderly persons, with some estimates much higher than the 5% figure derived from the NIMH study.3 Shapiro et a1 pointed out that, in the NIMH study, 81%-95% of elderly persons with mental health disorders had received no mental health treatment in the previous six month^.^ Of those who did receive mental health treatment, services were 1%to 6 times more likely to be provided by general medical providers than by mental health specialists. Among older people with acute and chronic medical problems, the prevalence of depression may be much higher than in the general elderly community population, with rates ranging from 15% to 45%.5-7However, general medical care providers detected only 9% to 12% of depressed elderly medical patients who presented for care.6 Depression is often not detected because elderly patients may not report the sadness or dysphoria that is commonly associated with depression. Instead, these patients have a "masked depression" and present with complaints that are somatic in nature.' A second reason that depression may be undetected is that elderly patients with medical conditions can also have coexisting depression that may be overshadowed by their medical problems. A third reason suggested by Rapp et a1 is "that house staff may not

have adequately inquired about specific signs and symptoms of depression."6 There are-brief office-based procedures that may be used by general medical providers to screen for those elderly patients who have depression. These procedures are brief questionnaires that are easily administered by the physician or other office personnel. Screening instruments that are used to validly detect depression in older adults must demonstrate certain measurement proper tie^.^' 9-12 Some studies have suggested that self-report measures that include items measuring somatic complaints may produce artificially elevated scores in the elderly due to non-depressionrelated somatic symptoms of physical illness, medication side effects, or aging-related sleep changes.13-15 Others have opined that somatic complaints may represent a somatization of an underlying depressive disorder and thus need to be assessed.8.16-1' Detecting such hidden or masked depression among elderly medical patients has been one of the more difficult tasks facing general physicians." Further, depression may co-exist with or be caused by medical disorders.17-20 These interacting disorders may cause somatic complaints that are symptoms of both depression and of a medical disorder. Several investigators have called attention to the proper role of dysphoria and somatic complaints as a possible limitation of construct validity of current assessment methods." 6r ', 19,'' The DSM-111-R requires the presence of a dysphoric mood to diagnose a depressive d i ~ o r d e r .However, ~ Blazer and Williams, Goldfarb, and Salzman and Shader note that elderly persons are less likely than younger counterparts to experience or report dysphoric mood, even if they are depressed.', 17,l9 Thus, screening instruments requiring dysphoric complaints would underdetect the prevalence of depression among these elderly respondents. Newmann3 identified a second diagnostic problem in-

D

From the 'Iatreia Institute, Fort Worth, Texas; and TDepartment of Health Services Administration, University of Alabama at Birmingham, Alabama. Presented at the 43rd Annual Scientific Meeting of the Gerontological Society of America, November 23, 1990. Address correspondence to George A. Foelker, Jr., PhD, Iatreia Institute, 1152 Country Club Lane, Ft. Worth, TX 76112. IAGS 40:259-262, I992 0 1992 by the American Geriatrics Society

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volving exclusionary criteria; the DSM-111-R does not diagnose depression if the symptoms are due to physical causes. Thus, deciding if a set of depression symptoms is caused by, versus co-exists with, a medical illness can substantially affect the valid detection of depression in elderly persons. There is a need for screening instruments for depression to have a balance between including some physical complaints as indexing depression, but not giving so much weight to those items that false-positive identifications of depression are made for medically ill or somatically involved elderly persons who are not indeed depressed.3,6,14,18,19,22 The present study evaluates a widely used screening instrument, the Center for Epidemiological Studies Depression ~cale.’~ The 20-item CES-D scale is a selfreport measure of the frequency with which depressive symptoms have been recent ty experienced. Important evidence of the validity of the CES-D was presented by Hertzog, Alstine, and Usala, who used confirmatory factor analysis to evaluate the measurement properties of the CES-D in two samples totalling 707 persons 20 to 80 years old.24The study found support for the measurement validity of the CES-D in screening for depression in older adults and for making comparisons across age groups. Further, Hertzog et a1 confirmed previous findings that the CES-D was composed of four separate but intercorrelated scales: Depressive Affect; Well-Being; Interpersonal Relations; and Somatic Symptoms.24 A concern noted by other researchers, however, is the possibility that very elevated Somatic Symptoms scores could produce false-positive screening results when the total CES-D score is used because of the number of chronic and acute health problems in elderly patients. Hertzog et a1 reported no age-related increase in the CES-D Somatic Symptoms scores, which suggests that any biasing influence of somatic symptomatology is reduced in the CBS-D relative to other selfreport scale^.'^ The present study evaluated more directly the extent to which ihe CES-D total score and the Somatic Symptoms score, in particular, were influenced by somatic symptomatology and the extent to which extreme scores on the Somatic scale could produce false positive diagnoses of depression.

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considered to be representative of the total rural and urban elderly population of the state. Based on a population cut-off of 100,000, counties were designated metropolitan or non-metropolitan. Non-metropolitan counties were further categorized as rural and urban, based on whether or not there was a city with a population over 1,200. Metropolitan counties comprised 84.1% of the sample, non-metropolitan counties, 18.6%of the sample. The sample’s mean age was 69.1 years. Educational level ranged from 1 year through post-graduate school, with a median of 11 years. Other demographic information for the overall sample is shown in Table 1. Measures Somatic symptomatology was operationalized using the Philadelphia Geriatric Center’s Multi-Level Assessment Instrument (MAI).26This instrument provides a comprehensive assessment of older persons with respect to health, activities of daily living, and social and psychological functioning. Specifically, the MA1 Physical Health Domain Index (PHDI) composite score and the scores from each of its three subindices (HI, HZ, H3) were used to measure somatic symptoms irrespective of cause (eg, physical illness or depression). The PHDI is composed of the self-rated health index (H1, summary score of four items), the health behavior index (Hz, total number of visits to the physician in the past year, days home in bed and time spent in hospital), and the health conditions index (H3, total number of physician-diagnosed medical conditions). The measurement properties reported for the MA1 indicate that the health domain is both valid and reliably measured by the PHDI and the three subindices (H1, HZ,and H3). Lawton et a1 found test-retest reliabilities and criterion-group and clinician-rating validity coefficients to be well within acceptable limits for measures of this type.26 Depression was measured using the CES-D. Respondents rate the frequency of depressive symptoms experienced during the past week with scores for each item ranging from 0 (less than 1 day) to 3 (5-7 days). The total score therefore ranges from 0 to 60. Scores were also obtained for each of the four scales which TABLE 1. SAMPLE CHARACTERISTICS PERCENT) Characteristic %

METHODS Subjects Data for this study were obtained from Ethnicity White the 1987 Statewide Survey of Alabama’s Elderly. The Black survey was sponsored by the Alabama Commission on Asian Aging and designed by researchers from the University Hispanic of Alabama at Birmingham Center for Aging.” The Status survey methodology was based on a random multi- Marital Mamed cluster samplingprocedure. Field supervisors from nine Widow(er) universities in Alabama were recruited for the survey Divorced/Separated and given 3 days of training. The supervisors in turn Never Mamed recruited and trained interviewers from their home Gender Female institutions. Field supervisors provided one phase of Male quality control by reviewing all interview forms and spot-checking with random phone calls. Data were Annual Income $15,000+ gathered from 1,060 individuals aged 55 and older 6,000-14,900 who resided in 13 counties considered to be representless than 6,000 ative of the entire state. The sampling frame was also

72.9 26.8 0.2 0.1 51.3 37.9 6.8 4.0 67.5 32.5 35.4 31.4 33.2

SOMATIC COMPLAINTS AND THE CES-D

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make up the total score: Somatic (seven items), De- scoring in the bottom one-third (n = 233) and those pressive Affect (seven items), Well-Being (four items), scoring in the top one-third (n = 210) of the distribution of PHDI scores. Those scoring in the middle third of and Interpersonal (two items).24 the PHDI distribution were omitted from this analysis. RESULTS Independent groups t tests indicated that the CES-D The distributions of CES-D and PHDI scores were total score and the Somatic, Well-Being, and Interperheavily skewed in the sample responses, as found also sonal scale scores were not significantly related to these by Hertzog et al.24 The raw scores were therefore high and low PHDI subgroup scores. However, the transformed (by log or square procedures) to produce Depressive Affect scale score was significantly different more normal distributions. Unless otherwise indicated, (barely) for the two groups (t = 1.98, P < 0.05, n = 443); those in the group with higher PHDI scores had the following results are for the transformed data. Age-related increases in the number of chronic and a larger mean Depressive Affect scale score = 2.9, acute health problems imply that the number of re- SD = 3.8) than those in the group with lower PHDI ported physical symptoms should also increase with scores = 2.2, SD = 3.4). Second, those respondents screened as depressed on age.14.18 The correlation coefficient between PHDI and age was computed as a method check to determine if the CES-D (a score of 16+) were evaluated to deterthe PHDI would measure the assumed positive rela- mine if they had significantly related somatic symp24 Of the total sample with complete tionship between increasing physical symptoms and tomatol~gy.~~, age. As expected, the PHDI score was positively related CES-D scores (n = 835), 156 met the criteria for depression (19%). This is in comparison to a rate of 14% in to age ( I = .21, P < 0.001). To assess the tendency of the CES-D and its four the Hertzog et a1 sample of 204 persons 60+ and to a scales to produce false-negative screenings of depres- rate of 22% in the Murrell, et a1 sample of 2,517 persons sion, two preliminary analyses were conducted. First, 55+.*'*24 Our depressed respondents were then divided correlation coefficients between age and the CES-D into two groups, again the upper and lower tertiles of total score and its four scale scores were computed. the PHDI score distribution. Independent-group t tests The results indicated that neither the CES-D total score indicated that only scores for the Somatic scale were nor any of the scale scores were significantly associated significantly different for those with high and low with age. Second, correlational analyses were used to somatic symptomatology (t = 2.49, P < 0.05); higher determine whether the CES-D total score or the four Somatic scale scores were associated with greater PHDI scale scores were associated with increasing somatic somatic symptoms. The other three scale scores and symptomatology as measured by the PHDI and its the CES-D total score were not significantly different scale scores. Results indicated that the CES-D total for the high and low PHDI scorers. The mean untransscore, and the Somatic, Well-Being, and Interpersonal formed Somatic scale score for the high-symptom scale scores were not significantly correlated with either group was 9.9 (SD = 4.6) whereas the mean for the the PHDI or its component scales, HI, Hz, and H3 low-symptom group was 7.5 (SD = 4.1); total possible (Table 2). However, the Depressive Affect scale score score was 21. was significantly, but perhaps not meaningfully, corAlthough those depressed respondents scoring highrelated with PHDI and HI (r = -.lo, n = 628, P < est on the Somatic scale had significantly (P < 0.05) 0.05; T = -.08, n = 628, P < 0.05, respectively). more reported PHDI complaints, it was unclear if they The previous results indicated that there was no had a clinically meaningful number of increased desubstantial relationship between somatic complaints pressive complaints. To evaluate that, the untransand the CES-D across the distribution of scores for formed mean Somatic score = 9.0, SD = 4.2) was both variables. However, to evaluate whether there compared to the mean Depressive Affect score (the was indeed an effect not apparent in the whole sample, only other scale with the same number of items, 7; two analyses were conducted on subsamples that = 8.2, SD = 4.1). A paired comparison t test indicated would be most likely to show the relationship. First, that although the mean Somatic score was significantly respondents were classified into two groups: those higher (f = 2.01, P C 0.05, n = 156), the untransformed

(x

(x

(x

TABLE 2. INTERCORRELATION MATRIX OF TOTAL AND SCALE SCORES FOR THE PHDI AND CES-D WellDepressive InterH2 H3 PHDI CESD Somatic beine Affect Dersonal Correlations H1 H1 H2 H3 PHDI

CESD Somatic Well-being Depressive affect Interpersonal * P < 0.01. ** P < 0.001.

1.oo .51** .51** .86**

-.07 -.02 -.06 -.08*

-.01

1.00 .45** .71**

1.00 .84**

.01 -.07

-.02 .01 -.01

-.04

-.06

-.04

-.05

.02

1.00 -.08

-.02 -.07 -.lo* -.01

1.00 .80**

.57** .87** .34**

1.oo .12** .62** .22**

1.00 .30** .08

1.oo .23**

1.00

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FOELKER A N D SHEWCHUK

mean difference of 0.76 clinically translates to respondents experiencing only one of the seven Somatic scale symptoms more frequently than 1 or 2 days per week. To determine if the respondents screened as depressed were disproportionately represented by those scoring high on the Somatic scale, a comparison was made of those respondents in the total sample who had extreme scores (Lll/z SD) on the Somatic (n = 69) and Depressive Affect scales (n = 88). VVhen the total sample was reduced to only those deemed depressed (n = 156), 65 of the 69 (94%) extreme scorers on the Somatic scale versus 81 of the 88 (92%) extreme scorers on Depressive Affect were represented.. DISCUSSION This study evaluated the relationship of somatic symptomatology as measured by the MA1 PHDI composite score and its three component indices (HI, HZ, Hs), with the CES-D total score and its four component scales. The results support the Hertzog et a1 suggestion that the CES-D and particularly the Somatic scale are relatively unbiased by the respondent’s somatic sympt~matology.’~ The CES-D total score and the Somatic scale were not related to age increases in the sample, PHDI composite scores, H1, HZ, or H3 index scores, or to subgroups of high and low scores on the PHDI composite score. In addition, among those screened as depressed by the CES-D, the PHDI composite score Hz, and H3 indices were not significantly and the H1, associated with the CES-D total score or three of the four subscales. Given the results of this study, the increased CES-D Somatic scale scores for those with the highest number of total PHDI somatic complaints do not represent an inordinate number of false-positive screenings for depression. Rather, the scores may indicate the same association between somatic complaints and actual medical illness found by Waxman et a1 using the Geriatric Depression Scale and the Cornell Medical Index.lS.27,28 The depressed respondents may have had more somatic complaints because of an interaction or mediating effect of depression and actual medical illness. It is possible that this mediating effect is measured to some extent by the CES-D Somatic scale. Our results suggest that the concern about the potential biasing effect of somatic complaints on depression screening using the CBS-D may need to be refocused. The issue should focus on the extent to which somatic complaints increase as medically ill persons experience depression. Depression may be a mediating variable in the relationship between medical illness and somatic complaints. Therefore, valid depression screening instruments should measure the increased somatic complaints. In that case, the CES-D would not be biased by somatic complaints but rather would reflect the expected effects of depression on medical illness-related somatic complaints. The sample for this study was comprised of community-dwelling elderly persons. Extending this assessment of the possible biasing effect of somatic com-

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plaints on the validity of the CES-D to special populations may help to determine whether indeed depression is a mediating variable in the relationship between medical illness and somatic complaints. Such special populations might include medically ill, hospitalized elderly patients and patients with chronic pain. REFERENCES 1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 3rd Ed., revised. Washington, DC, 1987. 2. Myers JK, Weissman MM, Tischler GH et al. Six-month prevalence of psychiatric disorders in three commuNties. Arch Gen Psychiatry 1984; 41:59-67. 3. Newmann JP. Aging and depression. Psychol Aging 1989;4;50-165. 4. Shapiro S, Skinner EA, Kessler LG et al. Utilization of health and mental health services. Arch Gen Psychiatry 1984;41:971-978. 5. Kitchell MA, Bames RF, Veith RC et al. Screening for depression in hospitalized geriatric medical patients. J Am Geriatr SOC 1982;30 174-177. 6. Rapp SR, Parisi SA, Walsh DA et al. Detecting depression in elderly medical inpatients. J Consult Clin Psychol 1988;56509-513. 7. Waxman HM, Camer EA. Physician‘s recognition, diagnosis and treatment of mental disorders in elderly medical patients. Gerontologist 1984;24:593597. 8. Goldfarb AF. Masked depression in the old. Am J Psychother 1967;21:791796. 9. Cunningham WR. Methodologicalcomment. Factorial invariance: A methodological issue in the study of psychological development. Exp Aging R ~ s1982;8(1):61-65. 10. Gallagher D, Thompson LW, Levy SM. Clinical psychological assessment of older adults. In. Poon LW, ed. Aging in the 1980s. Washington, D C American Psychological Association, 1980,pp 19-40. 11. Labouvie EW. Identity versus equivalence of psychological measures and constructs. In: Poon LW, ed. Aging in the 1980s.Washington, D C American Psychological Association, 1980,pp 493-502. 12. Zarit SH, Eiler J, Hassinger M. Clinical assessment. In. Birren JE, Schaie KE, eds. Handbook of the Psychology of Aging, 2nd Ed. New York Van Nostrand, 1985,pp 725-754. 13. Berry JM, Storandt M, Coyne A. Age and sex differences in somatic complaints associated with depression. J Gerontol 1984;39:465-467. 14. Bolla-Wilson K, Bleecker ML. Absence of depression in elderly adults. J Gerontol 1989;44:53-55. 15. Steur J, Bank L, OLsen E et al. Depression, physical health and somatic complaintsin the elderly: A study of the Zung self-rating depression scales. J Gerontol 1980;35:683-688. 16. Elkowitz EB, Viginia AT. Relationship of depression to physical and psychologic complaints in the widowed elderly. J Am Geriatr Soc 1980; 28:507-510. 17. Salzman C, Shader RI. Depression in the elderly. I. Relationship between depression, psychologic defense mechanisms, and physical illness. J Am Geriatr Soc 1978;26253-260. 18. Waxman HM, McCreary G, Weinrit RM et al. A comparison of somatic complaints among depressed and non-depressed older persons. Gerontologist 1985;25:501-507. 19. Blazer D, Williams CD. Epidemiology of dysphoria and depression in an elderly population. Am J Psychiatry 1980;137439-444. 20. Murrell SA, Himmelfarb S, Wright K. Prevalence of depression and its correlates in older adults. Am J Epidemiol1983;117173-185. 21. Foelker GA Jr, Shewchuk RM, Niederehe G. Confirmatory factor analysis of the Short Form Beck Depression Inventory in elderly community samples. J Clin Psychol 1987;43:111-118. 22. Newmann JP, Engel RT, Jensen J. Depressive symptom patterns among older women. Psychol Aging 1990;5:101-118. 23 Radloff LS. The CES-D scale: A self-report depression scale for research in the general population. Appl PsychologicalMeas 1977;1:385-401. 24 Hertzog C, Alstine JV,Usala PD et al. Measurement properties of the Center for Epidemiological Studies Depression Scale (CES-D) in older populations. Psychological Assessment. J Consult Clin Psychol 1990;1:6472. 25 Alabama Commission on Aging and University of Alabama Center fo Aging. (1987). Statewide Survey of Alabama‘s Elderly. (Available fron University of Alabama at B-gham Center for Aging, MT730, Univet sitv Center, Birmingham AL, 35294). 26. Lawton MP,MossM, Fulcomer M e t al. A research and service oriente multi-level assessment instrument. Gerontologist 1982;37:91-99. 27. Yesavage JA, Rose TL, Lum 0 et al. Development and validation of geriatric depression screening scale: A preliminary report. J Psychiatr R 1983;1737-49. 28. Broadman K, Erdmann AJ, h r g e I et al. The Cornell Medical Index-Heal Questionnaire I1 as a diagnostic instrument. JAMA 1951;142:152-157.

Somatic complaints and the CES-D.

To evaluate the Center for Epidemiology Surveys-Depression (CES-D) scale for inordinate false positives, due to measurement of non-depression-related ...
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