J O U R N A L O F

AFFECTIVE DISORDERS

Journal of Affective Disorders 36 (1995) 65-75

Research report

Major and minor depression in later life: a study of prevalence and risk factors

Aartjan T.F. Beekrnan Dorly J.H Deeg ", Theo van Tilburg b, Jan H. Smit b,

Chris Hooijer ", Willem van Tilburg a

" Department of Psychiatry, Free University of Amsterdam, Amsterdam, The Netherlands Department of Sociology and Social Gerontology, Free U n i v e r s i ~ of Amsterdam, Amsterdam, The Netherlands

Received 9 May 1995; revised 18 July 1995; accepted 18 July 1995

Abstract

In this paper, the results of a community-based study into the prevalence and risk factors associated with depression in the older (55-85 years) population of The Netherlands are presented. The prevalence of major depression was 2.02%, that of minor depression 12.9%, while 14.9% had clinically relevant levels of depressive symptoms. Associations with a comprehensive set of risk factors were not affected dramatically by age or sex. However, comparing major to minor depression, risks were substantially differently distributed. It appears that major depression is more often an exacerbation of a chronic mood disturbance, with roots in long-standing vulnerability factors; while minor depression is more often a reaction to the stresses commonly experienced in later life.

Keywords: Depression; Elderly; Community; Prevalence; Risk factor

1. Introduction

Along with the dementias and anxiety disorders, depression is the most common psychiatric distur- bance in late life (Blazer, 1989, Beekman et al., 1993). The evidence of studies conducted so far is that depression is associated with declines in well- being and levels of daily functioning (Wells et al., 1989; Gurland, 1992); and a higher risk of functional impairment, mortality and use of health services

* Corresponding author. Address: Department of Psychiatry, Free University of Amsterdam, Valerius Clinic, Valeriusplein 9, 1075 BG Amsterdam, The Netherlands.

(Gurland, 1983; Burvill and Hall, 1994; Beekman et al., 1995). While depression is generally thought to be a treatable disorder, the recognition and provision of adequate treatment has been shown to be rather poor (Copeland et al., 1992; Kirmayer et al., 1993). From a public health perspective, depression may be one of the more prevalent and potentially amenable factors involved in the pathways leading to utiliza- tion of the health services by older people. Despite this long-standing interest, there is no consensus on basic issues, such as the influence that age and age-related developments may have on the preva- lence of depression (Newman, 1989). In the ECA studies, and in studies using similar methodology, very low prevalence rates for major depression have

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66 A.T.F. Beekman et al./Journal of Affective Disorders 36 (1995) 65-75

been found (Table 1). Here, rigorous diagnostic cri- teria, developed in clinical psychiatry among younger adults, were operationalized for use in community- based samples of the elderly. Studies using a broader definition of clinically relevant depression have yielded much higher prevalence rates (Table 1). Here, definition of caseness was determined by the level of depressive symptomatology and the likelihood that intervention would be deemed necessary by clini- cians. This divergence of findings has prompted discussion as to the validity of current diagnostic criteria for depressive disorders among the elderly (Blazer, 1994). Recognising this problem, the recent NIH consensus conference on late-life depression has called for studies involving not only those fulfill- ing rigorous diagnostic criteria (Blazer, 1994). In the proceedings of that conference, reference is made to 'major depression' when rigorous diagnostic criteria are fulfilled, and to 'minor depression' in all other cases of clinically relevant depression.

Within the older population, prevalence rates of

Table 1 Prevalence of depression in elderly: results of community-based studies

both minor and major depression appear to shift. The prevalence of major depression tends to decrease among the older-old, while the prevalence of minor depression seems to be highest in the oldest age groups (Newman, 1989). Most current theoretical models on the etiology of depression reflect the general stress-diathesis model (Brown and Harris, 1978). In this model, disturbances in the interplay between vulnerability and stress are decisive for the development of depression. Within the older popula- tion, the prevalence of most established risk factors for depression changes. For example, among the older-old, there is an increased probability of physi- cal illness, loss of loved ones and cognitive decline. On the other hand, through excess mortality among those depressed at younger ages, the least vulnerable individuals may be expected to reach the older-old age strata (Burvill and Hall, 1994). The net effect may be either an increase, decrease or stability of the rates of depression with age. Clearly, age-related changes in the patterns of risk factors should be

Reference n Instrument Prevalence (%)

Major depression Weissman and Myers (1 978) Blazer and Williams (1980) Gurland (1 983) Kay et al. (1 985) O'Hara et al. (1985) Copeland et al. (1987) Bland et al. (1988) Weissman et al. (1988) Lindesay et al. (1989)

Minor depression Gurland (1983) Copeland et al. (1987) Lindesay et al. (1989)

Major + minor Blazer and Williams (1980) Frerichs et al. (1981) Eaton and Kessler (198 1) Murrell et al. (1983) Romaniuk et al. (1983) Kay et al. (1985) O'Hara et al. (1985) Berkrnan et al. (1986) Kennedy et al. (1989) Livingstone et al. (1990) Blazer et al. (1991) Fuhrer et al. (1992)

RDC DSM-I11 CARE/ICD GMS/DSM-I11 RDC GMS/AGECAT " DIS DIS CARE CARE/ICD ' GMS/AGECAT CARE OARS CES-D CES-D CES-D OARS GMS CES-D CES-D CES-D CARE ' CES-D CES-D

m, men; w, women. a Depressive psychosis; severe depression; ' pervasive depression; depressive neurosis; mild depression.

A.T.F. Beekman et al./ Journal of Affective Disorders 36 (1995) 65-75

taken into account in studies of the prevalence of late-life depression. Moreover, the validity of current diagnostic criteria would be greatly enhanced if a clear pattern of risk factors emerged from such stud- ies.

The leading hypothesis of the current study was that major and minor depression are determined by different sets of risk factors, explaining their differ- ing associations with age. To this end, data will be presented regarding (1) the prevalence of both major and minor depression, and (2) age-related shifts in the patterns of associations with both vulnerability and stress.

2. Methods

2.1. Sampling and procedures

The Longitudinal Aging Study Amsterdam (LASA) is a 10-year longitudinal study on predictors and consequences of changes in well-being and au- tonomy in the older population (Deeg et al., 1993). It was aimed to obtain a sample representative of older (55-85 years) males and females in various age categories and geographic regions of the Dutch pop- ulation. Random samples were drawn from popula- tion registers in municipalities in three regions of The Netherlands (Fig. 1). One middle to large city, and two or more rural municipalities were included in each region. In order to be able to study age and sex differences, the sample was stratified for age and sex. To ensure large enough numbers in all cells 5 years into the study, the number of males and fe- males in each category was weighted using projected survival rates (CBS, 1993). In this way, the older-old were rather heavily oversampled. Persons aged 85 and above were excluded, because the attrition rate of this age group was expected to be too high over the 10-year study period. Full details on the method- ology of the sampling procedure are reported else- where (Broese van Groenou et al., 1994). For rea- sons of economy, the sample was used in two stud- ies: NESTOR-LSN (van Tilburg et al., 1992) and LASA. Respondents were first interviewed by the NESTOR-LSN team and - 10 months later by one of the LASA interviewers. The response rate for the NESTOR-LSN interview was 62.3%. As expected,

Fig. 1. Location of the 1 1 municipalities in the Netherlands.

nonresponse was associated with age (P < 0.05), sex ( P < 0.05) and urbanicity ( P < 0.05). The older-old, females and those living in more urbanized areas were less likely to respond. Paradoxically, stratifica- tion has lead to a lower response, but has ensured representativity on these important characteristics of the sample (Broese van Groenou et al., 1994). For LASA, all 3805 respondents to NESTOR-LSN were approached, of whom 3107 (81.7%) took part (Smit and de Vries, 1994). 394 (10.4%) refused to partici- pate due to lack of interest; 134 (3.5%) were too ill or cognitively impaired to be interviewed; 126 (3.3%) died before being interviewed and 44 (1.2%) persons could not be contacted. Attrition was related to age ( P < 0.001), but not to sex. As expected the older-old were more often found to be too ill or cognitively impaired to participate ( P < 0.05). Due to item non- response on the dependent variable a further 51 subjects were lost, leaving a study sample of 3056. Depression was diagnosed using a two-stage screen- ing design. The second stage of case-finding took place in an additional interview, scheduled 2-8 weeks after LASA-baseline (average 32.6 days). Response here was 86.0% relative to LASA baseline. Again, response was related to age ( P < 0.001), but not to sex. Details on the screening procedure are described in the measurements section.

All interviews were conducted in the homes of

68 A.T.F. Beekman et al./Journal of Affective Disorders 36 (1995) 65-75

respondents by specially trained and intensively su- pervised interviewers. Two sets of interviewers were recruited and trained for the baseline and diagnostic interviews, respectively, ensuring that screening and diagnosis of depression were not administered by the same interviewer. All interviews were tape-recorded in order to control the quality of the data. Interview- ers worked with laptop computers and were encour- aged to record any disturbance in the course of the interview. Interviews were conducted between Octo- ber 1992 and September 1993.

2.2. Measures

2.2.1. Measuring depression Minor depression was defined as all clinically

relevant depressive syndromes, not fulfilling rigorous diagnostic criteria for major depression. The preva- lence of minor depression was measured using the Center for Epidemiologic Depression Scale (CES-D, Radloff, 1977). This is a 20-item self-report scale developed to measure depressive symptoms in the community. It has been widely used in older commu- nity samples (Table I), and has good psychometric properties in elderly samples (Himmelfarb and Mur- rell, 1983; Hertzog et al., 1990; Radloff and Teri, 1986). The Dutch translation had similar psychomet- ric properties in three previously studied samples of elderly in The Netherlands (Beekman et al., 1994). The overlap with symptoms of physical illness has been shown to be minimal in a number of studies (Berkman et al., 1986; Foelker and Shewchuk, 1992). The CES-D generates a total score which can range from 0-60. In order to identify respondents with levels of depression which are clinically relevant, we used the generally used cut-off score 2 16 (~eekman et al., 1994).

Major depression was defined according to DSM- I11 criteria, and operationalised using an adapted version of the Diagnostic Interview Schedule (DIS, Robins et al., 1991). The DIS is a criterion instru- ment which was also designed specifically for use in epidemiological studies. It has been used widely in elderly samples (Table 1). All subjects scoring r 16 on the CES-D in the baseline interview and a simi- larly sized random sample of those scoring < 16 were approached for the diagnostic interviews. In total, 660 diagnostic interviews were obtained, of

which 329 (50%) in subjects scoring above the cut-off on the CES-D. In order to calculate point prevalence rates of major depression, further selection of re- spondents was necessary on the basis of the lag-time between screening and diagnosis. The CES-D has a time range of 1 week. The DIS has various measures of recency, but depressive symptoms have to be present for at least 2 weeks before they are consid- ered in diagnosis. Taking the 1-month recency of DIS diagnoses as a base, the maximum lag-time allowable is 6 weeks. Therefore, for the calculation of the 1-month prevalence of major depression, only subjects for whom the lag-time was less then 42 days were included. This reduced the diagnostic sample from 660 to 487 subjects (average lag-time 20.7 days). Criterion validity of the CES-D for major depression (1-month recency) was excellent (sensi- tivity loo%, specificity 88%) (Beekman et al., 1995).

2.3. Independent variables

In a survey of the literature (Beekman et al., 1993), 11 domains of variables were identified, which have been shown to be associated with depression in the elderly. These are age, sex, urbanicity, socioeco- nomic status, physical health, life events (recent and long-term), social and interpersonal support, person- ality, comorbidity with other psychiatric distur- bances, psychiatric history and genetic vulnerability. Level of education was used as a measure of socioe- conomic status. Physical health was measured by self-report. Measures include the presence of chronic physical diseases (CBS, 1989), functional limitations (van Sonsbeek, 1988) and self-perceived health (CBS, 1989). Measures of social support were con- structed from a questionnaire which included de- tailed questions on both the number and the quality of contacts with members of the social network (van Tilburg et al., 1992). In this paper, we report on the size of the contact-network, and the exchange of instrumental and emotional support with network members. Loneliness was assessed with a separate scale (de Jong-Gierveld and Kamphuis, 1985). A measure of locus of control (Pearlin and Schooler, 1978) was included as a personality characteristic which may influence levels of depression. The Mini Mental Status Examination (Folstein et al., 1975) was included as a measure for cognitive functioning.

A.T.F. Beekman et al./ Journal of AfSectiue Disorders 36 (1995) 65-75 69

The LASA baseline interview contained the CES-D and all the above correlates of depression. Data on life-events and psychiatric and family history are available only for those in whom a diagnostic inter- view took place. Life events include catastrophic events experienced in early childhood (five items regarding parental loss, serious personal illness, ne- glect and physical and sexual abuse); extreme expe- riences during the second world war which have had a lasting effect (one item); and interpersonal losses, separations and conflicts experienced during the past year (seven items). Partner loss during the past year was one of the latter seven items. Because of its importance, this event is also reported on separately. Personal histories for major depression were derived from the DIS. Family histories of affective disorders, anxiety disorders, substance abuse and conduct dis- orders were assessed with a questionnaire con- structed for the present study. Treatment history was similarly assessed with a separate questionnaire. All scales were either previously validated in compara- ble samples in The Netherlands, or in LASA pilot studies (Deeg et al., 1993).

2.4. Data analysis

this sample, the probability distribution of major depression for different values on the CES-D was ascertained. The observed probabilities were then used as weights in the baseline study sample to derive the estimated 1-month prevalence of major depression. The prevalence of minor depression was obtained by subtracting the prevalence of major de- pression from the percentage scoring above the cut- off on the CES-D. Bivariate associations with inde- pendent variables were assessed by calculating odds ratios. For these analyses, all independent variables were dichotomised. 95% confidence intervals were calculated in all cases. When the 95% confidence interval did not include 1, the association was re- garded to be statistically significant. In stratified analyses, odds ratios for minor depression were cal- culated for the sexes and three age groups separately. Due to the low number of subjects with 1 month prevalence of major depression, analysis of risk fac- tors was not feasible. To accommodate for this, the 6-month prevalence of major depression was used in analyses of risk factors. All odds ratio's were calcu- lated relative to the group with the lowest preva- lence. In order to compare risk factors for major and minor depression, subjects with major depression

The 1-month prevalence of major depression was were excluded when minor depression was under calculated using the diagnostic sample (n = 487). In study, and visa versa. In this way, major and minor

Table 2 Characteristics of LASA baseline sample

Characteristic n (96) 1 Characteristic n (96)

Age 55-64 65-74 75-85

Sex males females

Level of education Low Middle High Urbanicity Living in Amsterdam Living elsewhere Marital status Married Not/no longer married Living arrangement Independent Old-age residence Nursing home/hospital

Depressive symptoms CES-D < 16 CES-D 2 16 Cognitive functioning MMSE < 24 MMSE(23 Chronic physical illness None One or more Physical limitations None One or more Perceived health

i Very good/good I Fair/poor

Table 3 The prevalence of major and minor depression by age and sex

55-59 60-64 65-69 70-74 75-79 80-85 Total

male female all male female all male female all male female all male female all male female all male female

n 217 214 431 248 285 533 215 279 494 227 233 460 295 275 570 276 292 568 1478 1578 Major 1.5% 1.1% 1.3% 0.8% 2.2% 1.6% 0.6% 2.7% 1.8% 1.1% 3.1% 21% 1.9% 3.2% 2.5% 2.2% 3.2% 2.7% 1.4% 2.6% depression Minor 10.9% 8.0% 9.4% 6.5% 13.3% 9.9% 6.4% 15.2% 11.4% 9.5% 14.9% 12.2% 12.7% 19.7% 16.1% 11.6% 21.5% 16.7% 9.8% 15.7% depression Maj+ 12.4 9.1% 10.7% 7.3% 15.5% 11.5% 7.0% 17.9% 13.2% 10.6% 18.0% 143% 14.6% 22.9% 18.6% 13.8% 24.7% 19.4% 11.2% 18.3% minor dep Totals 43 1 533 494 460 5 70 568 3056

A.T.F. Beekman et al./Journal of Affective Disorders 36 (1995) 65-75 7 1

depression were both contrasted with the same, non- depressed, control group.

3. Results

3.1. Characteristics of sample

In Table 2, demographic and health-related char- acteristics of the sample are shown. Due to the sampling procedure men and women are roughly evenly represented. The higher proportion of older- old reflects the intended even distribution of subjects 5 years into the study. The relatively high number of subjects unmarried, with cognitive impairment or physical health problems is a function of oversam- pling among the older-old. It also shows that attrition has not caused the sample to become a sample of 'healthy elderly'. The low percentage in institutions reflects selective nonresponse.

3.2. Prevalence of depression

In this sample, the 1 month prevalence of major depression was 2.02%; that of minor depression was 1 2.9%; while the prevalence of all probably clini- cally relevant depressive syndromes (major plus mi- nor depression) was 14.9%. In Table 3, the preva- lence rates are presented by age and sex. For both major and minor depression, the lowest prevalence

Table 4 Relative risk of major and minor depression for independent variables

rates were found in the youngest-old, gradually ris- ing with age (P < 0.001). Except in the youngest age group, women had higher prevalence rates for both major and minor depression. On the whole, the prevalence of both major and minor depression was roughly twice as high for women ( P < 0.001). How- ever, associations with age appeared to be different for men and women. In men, the prevalence of both major and minor depression seemed lowest between age 60-70. In the older-old men, the prevalence of major depression increased, while the prevalence of minor depression fluctuated around the level of the youngest age group. In women, there appeared to be a monotonic increase of both major and minor de- pression with age.

3.3. Associations with independent variables

In Table 4, the relative risks for major and minor depression are presented for independent variables. Due to the lower numbers involved the confidence intervals for major depression are wider. Considering minor depression, there were significant associations with all independent variables, except instrumental support received and emotional support given. In stratified analyses (results not shown), the risks for minor depression were very similar for men and women, and across age groups. The risk for men was higher than women when unmarried and with low levels of emotional support received (relative risk for

Independent variable Minor depression Major depression

Marital status not/no longer married 2.74 (2.21 -3.38) 1.8 (1.03-3.14) Level of education low level 1.17 (1.39-2.11) 1.66 (0.95-2.89) Urbanicity living in Amsterdam 2.04 (1.65-2.54) 0.78 (0.4- 1.52) Chronic physical illness one or more 2.37 (1.83-3.07) 1.37 (0.75-2.52) Functional limitations one or more 4.02 (3.21 -5.04) 2.37 (1.35-4.18) Perceived health fair/poor 4.43 (3.54-5.54) 6.13 (3.25-1 1.54) Cognitive impairment MMSE < 24 2.27 (1.74-2.85) 1.97 (0.9-4.28) Network size < 50 percentile 2.03 (1.6-2.56) 0.9 (0.5- 1.61) Instrumental support received < 50 percentile 1.01 (0.81-1.27) 0.5 1 (0.28-0.95) Instrumental support given < 50 percentile 1.94 (1.53-2.45) 1.02 (0.57- 1.83) Emotional support received < 50 percentile 1.36 (1.09-1.71) 0.85 (0.47- 1.53) Emotional support given < 50 percentile 1.13 (0.9- 1.42) 0.9 (0.5-1 -62) Loneliness < 50 percentile 6.26 (4.86-8.08) 10.41 (4.58-23.69) Internal locus of control < 50 percentile 4.38 (3.44-5.58) 10.95 (4.55-26.33)

72 A.T.F. Beekman et al . / Journal of Affective Disorders 36 (1995) 65-75

men higher and outside the 95% confidence interval for women). Compared with the old-old (75-85), the risks for the young-old (55-65) were higher when unmarried, with poor subjective health and with low levels of emotional support received (relative risk for the young-old higher and outside the 95% confi- dence interval of the old-old).

Concerning major depression, significant associa- tions were found for marital status, functional limita- tions, subjective health, instrumental support re- ceived, loneliness and locus of control. Risks for major depression were very similar for men and women, and across three age groups (results of stratified analyses not shown). The old-old had a higher risk for major depression when unmarried, which is opposite to what was found for minor depression.

Comparing risk factors for major and minor de- pression revealed more differences. In major depres- sion, associations were stronger with self-perceived health, instrumental support received, loneliness and locus of control. Associations were notably weaker for marital status, urbanicity, chronic diseases, func- tional limitations, size of the contact-network, instru- mental support given, and emotional support re- ceived (risks for major depression lower and outside the 95% confidence interval of minor depression).

In Table 5, the relative risks for major and minor depression are shown for family history, a personal history with major depression, life events and treat- ment history. These independent variables were available only for those participating in the diagnos- tic interview. Catastrophic events experienced in early childhood had a modest, but significant associ- ation with minor depression, and no association with

Table 5 Relative risks for major and minor depression for life-events and family, personal and treatment histories

Independent variable Minor depression Major depression

Family history 1.53 (1.03-2.26) 2.66 (1.45-4.89) Personal history 4.06 (2.25-7.32) 90.82 (39.07-21 1.13) major depression Events 0-6 years 1.78 (1.17-2.71) 1.51 (0.73-3.14) Events war 2.33 (1.52-3.55) 2.08 (1.03-4.2) Events past year 1.35 (0.98- 1.87) 1.69 (0.94-3.02) Loss of partner 8.53 (2.51-29.01) 12.78 (3.09-52.76) past year

major depression. Extreme experiences during the second world war were associated with about a 2-fold increase in the prevalence of both major and minor depression. More recently experienced events (past year) did not seem to be associated with in- creased risks for either type of depression. However, when partner loss during the past year was consid- ered separately, the risks for both major and minor depression were very high and statistically signifi- cant. A positive family history of affective, anxiety, substance abuse or conduct disorders was signifi- cantly associated with both major and minor depres- sion. The risks for major depression was stronger (relative risk outside the 95% confidence interval of minor depression). Finally, subjects with previous episodes of major depression had about a 4-fold increased risk for minor depression, while the risk for major depression was extremely high (relative risk 91, 95% confidence interval 39-21 1).

4. Discussion

In this sample of older subjects in The Nether- lands, the prevalence rates of major and minor de- pression were 2.02% and 12.9%, respectively. The prevalence of all probably clinically relevant depres- sive syndromes was 14.9%. Compared with studies conducted elsewhere, using comparable definitions of depression and research methods, the prevalence rates found are very similar (Table 1). However, due to stratification of the sample and nonresponse, the actual prevalence of depression in the Dutch elderly may be suspected to differ. Stratification for age and sex has had a negligible effect on prevalence rates. Weighted back to the actual age and sex distributions in the Dutch population in 1993 (CBS, 1993), preva- lence rates were 2.03 for major depression, 12.8 for minor depression and 14.8 for all types of depression combined. Although inaccuracies caused by nonre- sponse cannot be ruled out, this demonstrates the beneficial effect the sampling strategy has had on the representativeness of the sample. Furthermore, the effort made to obtain even numbers in all relevant strata has lead to a study sample in which risk factors for depression are well-represented, and which is well-suited to study the effects of age and sex. Paradoxically, through oversampling in exactly those strata with the lowest response, this has lead to

A.T.F. Beekman et al./Journal of Affective Disorders 36 (1995) 65-75 73

considerably higher nonresponse rates. In this way, gains made in representativity of the sample are counterbalanced by a lower response. Clearly, the institutionalised elderly are not well-represented in the sample. Results cannot be generalized to these groups. However, as most of the previous studies listed in Table 1 were restricted to elderly living independently in the community, the present findings can be readily compared.

Except in the youngest age group, women had higher prevalence rates for both major and minor depression than men. Rising rates of depression with age were only found for women. In men, there was no clear association with age. A broad range of risk factors, representing different aspects of vulnerability and stress, were selected from the literature (Beekman et al., 1993) to be included. Bivariate associations of both major and minor depression with risk factors did not differ dramatically between the sexes or age groups. However, comparing risks for major and minor depression, patterns of risk factors did seem to differ greatly. Associations with minor depression were stronger for subjects unmarried; living in a large city; those in poor health (chronic diseases and functional limitations); and those with smaller con- tact-networks or less exchange of most of the social support indices. Associations with major depression were stronger for self-perceived health, loneliness, low instrumental support received, internal locus of control, family history and previous episodes.

Associations with self-perceived health and lone- liness are likely to be inflated, because these experi- ences may be part of the depressive syndrome. It is therefore not surprising that associations with these two 'independent variables' is higher for more se- vere types of depression. Report bias, in which de- pressed individuals are more prone to remember and report negatively, is a second mechanism potentially leading to inflated relative risks on many of the independent variables studies. Because all data were based on self-report, there is no conclusive way to rule out either report or recall bias. However, one would expect higher relative risks in more severe (major) depression on variables prone to this type of bias. Moreover, report bias is expected to be a stronger factor in variables in which the evaluation of the subject plays a larger part. Recall bias is expected to be stronger in those with severe depres-

sion and perhaps in the older-old. No such trends are readily visible in the patterns of risk factors found. Because the data are cross-sectional, temporal rela- tionships between depression and most risk factors cannot be studied. This precludes establishment of cause-effect relationships in the data. The patterns of associations can however be used as tentative indica- tions for etiologic differences between major and minor depression, and for major shifts in risk factors with age and sex. As was shown, relative risks did not dramatically change with age or sex. Considering risk factors more strongly associated with minor than with major depression, they are all indicative of either 'less exchange with important others', or of 'more physical health problems'. Both domains rep- resent stressors frequently confronting elderly. Risk factors more strongly associated with major depres- sion include personality, and both family and per- sonal history. These are variables representing long- standing personal vulnerability for depression. A ten- tative etiologic model may be postulated, in which the distinction between major and minor depression is far more important than distinctions between ei- ther the sexes or the young vs. the older-old. Minor depression is associated with a variety of stresses. Major depression is more strongly associated with vulnerability factors such as personality (locus of control), heredity (family history) and previous his- tory. The extremely strong association between per- sonal history and major depression confirms the high risk of recurrence of major depression found in previous studies (Kiloh et al., 1988).

A tempting conclusion is that major depression in the elderly is more often the exacerbation of a chronic mood disturbance, with roots in long-stand- ing personal vulnerability; while minor depression is more often a reaction to the stresses encountered in later life. If corroborated in longitudinal studies, this could have major implications for clinical practice. In minor depression, this would lead to interventions primarily aimed at the amelioration of effects of current stresses, such as lack of interpersonal support and impaired daily functioning due to physical ill- ness. In major depression, treatment regimens with proven efficacy in younger psychiatric samples should not be delayed.

Finally, these data suggest that formal diagnostic criteria for major depression usefully define a disor-

74 A.T.F. Beekman et al . / Journal of Affectiue Disorders 36 (1995) 65-75

der, which is etiologically distinct from the large body of clinically relevant depressive syndromes en- countered in late life. This goes against conceptualis- ing major and minor depression as expressions of a continuum of one underlying disorder. Furthermore, returning to the debate about the 'true prevalence' of depression in later life, it seems fruitful to consider both major and minor depression in future studies.

Acknowledgements

This study is based on data collected in the con- text of the Longitudinal Aging Study Amsterdam (LASA), which is funded by the Ministery of Wel- fare, Health and Sports of The Netherlands.

References

Beekman, A.T.F., van Tilburg, W. and Deeg, D.J.H. (1993) Depression in the elderly: a review of community based studies. Tijdschr. Psychiatrie 35, 154- 168.

Beekman, A.T.F., van Limbeek, J., Deeg, D.J.H., Wouters, L. and van Tilburg, W. (1994) Screening for depression in the elderly in the community: using the Center for Epidemiologic Studies Depression scale (CES-D) in The Netherlands. Tijdschr. Gerontol. Geriatr. 25, 95- 103.

Beekman, A.T.F., Deeg, D.J.H., van Limbeek J., Braam, A.W., de Vries, M.Z. and van Tilburg, W. (1995) Criterion validity of the Center for Epidemiologic Studies Depression scale (CES- D): results from a community-based sample of older subjects in The Netherlands. Accepted for publication in Psychol. Med.

Berkrnan, L.F., Berkrnan, C.S., Kasl, S.V., Freeman, D.H., Leo, L., Ostield, A.M., Coroni-Huntly, J. and Brody, J.A. (1986) Depressive symptoms in relation to physical health and func- tioning in the elderly. Am. J. Epidemiol. 124, 372-388.

Bland, R.C., Newman, C. and Om, H. (1988) Prevalence of psychiatric disorders in the elderly in Edmonton. Acta Psychi- atr. Scand. 77, 57-63.

Blazer, D.G. and Williams, C.D. (1980) Epidemiology of dyspho- ria and depression in an elderly population. Am. J. Psychiatry 137, 439-444.

Blazer, D.G. (1989) Depression in the elderly. N. Engl. J. Med. 320, 164-166.

Blazer, D.G., Burchett, B., Service, C. and George, L. (1991) The association of age and depression among the elderly: an epidemiologic exploration. J. Gerontol. 46, 2 10-2 15.

Blazer, D.G. (1994) Epidemiology of late-life depression. In: Diagnosis and Treatment of Late Life Depression; Results of the NIH Consensus Development Conference. APA, Washing- ton, DC, pp. 9-21.

Broese van Groenou, M.I., van Tilburg, T.G., de Leeuw, E.D. and

Liefbroer, A.C. (1994) Data collection. In: Living Arrange- ment and Social Networks of Older Adults, First Results. Free University, Amsterdam, The Netherlands, pp. 1 - 19.

Brown, G.W. and Harris, T. (1978) Social origins of depression: a study of psychiatric disorder in women. Free Press, New York, NY.

Burvill, P.W. and Hall, W.D. (1994) Predictors of increased mortality in elderly depressed patients. Int. J. Geriatr. Psychia- try 9, 219-227.

Central Bureau of Statistics (1989) Health Interview Questionaire. CBS, Heerlen, The Netherlands.

Central Bureau of Statistics (1993) Statistical Yearbook. CBS, The Hague, The Netherlands.

Copeland, J.R.M., Dewey, M.E., Wood, N., Searle, R., Davidson, I.A. and Mc William, C. (1987) Range of mental illness among the elderly in the community. Br. J. Psychiatry 150, 815-823.

Copeland, J.R.M., Davidson, I.A., Dewey, M.E., Gilmore, C., Larkin, B.A., Mc William, C., Saunders, P.A., Scott, A., Sharma, V. and Sullivan, C. (1992) Alzheimer's disease, other dementias, depression and pseudodementia: prevalence, inci- dence and three-year outcome in Liverpool. Br. J. Psychiatry 161, 230-239.

Deeg, D.J.H., Knipscheer, C.P.M. and van Tilburg, W. (1993) Autonomy and well-being in the aging population: concepts and design of the Longitudinal Aging Study Amsterdam. NIG-trend-studies No. 7. Netherlands Institute Gerontology, Bunnik, The Netherlands.

Eaton, W.W. and Kessler, L.G. (1981) Rates of symptoms of depression in a national sample. Am. J. Epid. 114, 528-538.

Foelker, G.A. and Shewchuk, R.M. (1992) Somatic complaints and the CES-D. JAGS 40, 259-262.

Folstein, M.F., Folstein, S.E. and Mc Hugh, P.R. (1975) 'Mini- mental state'. A practical method for grading the cognitive state of patients for the clinician. J. Psychiatr. Res. 12, 189- 198.

Frerichs, R.R., Aneshensel, C.S. and Clark, V. (1981) Prevalence of depression in Los Angeles county. Am. J. Epid. 113, 69 1-699.

Fuhrer, R., Antonucci, T.C., Gagnon, M., Dartigues, J.F., Bar- berger-Gateau, P. and Alperovitch, A. (1992) Depressive symptomatology a and cognitive functioning: an epidemiologi- cal survey in an elderly community sample in France. Psychol. Med. 22, 159-172.

Gurland, B.J. (1983) The Mind and Mood of Aging. Haworth Press, New York, NY.

Gurland, B.J. (1992) The impact of depression on quality of life of the elderly. Clin. Ger. Med. 8, 377-386.

O'Hara, M.W., Kohout, F.J. and Wallace, R.B. (1985) Depression among the rural elderly. J. Nerv. Ment. Dis. 173, 582-589.

Hertzog, C., van Alstine, J., Usala, P.D., Hultsch, D.F. and Dixon, R. (1990) Measurement properties of the center for epidemio- logical studies depression scale (CES-D) in older populations. Psychol. Assess. 2, 64-72.

Himmelfarb, S. and Murrell, S.A. (1983) Reliability and validity of five mental health scales in older persons. J. Gerontol. 38, 333-339.

A.T.F. Beekman et al. / Journal of Affective Disorders 36 (1995) 65-75 75

de Jong-Gierveld, J. and Kamphuis, F.H. (1985) The development of a Rasch-type loneliness scale. Appl. Psychol. Meas. 9, 289-299.

Kay, D.W.K., Henderson., A.S., Scott, R., Wilson, J., Rickwood, D. and Grayson, D.A. (1985) Dementia and depression among the elderly living in the Hobart community: the effect of the diagnostic criteria on the prevalence rates. Psychol. Med. 15, 77 1-788.

Kennedy, G.J., Kelman, H.R., Wisniewsky, W., Metz, H. and Bijur, P. (1989) Hierarchy of characteristics associated with depressive symptoms in an urban elderly sample. Am. J. Psychiatry 146, 220-225.

Kiloh, L., Andrews, E. and Nilson, M. (1988) The long-term outcome of depressive illness. Br. J. Psychiatry 153, 752-757.

Kirmayer, L.J., Robbins, J.M., Dworkind, M. and Yaffe, M.J. (1993) Somatization and the recognition of depression and anxiety in primary care. Am. J. Psychiatry 150, 734-741.

Lindesay, J., Briggs, K. and Murphy, E. (1989) The Guy's age concern survey: prevalence rates of cognitive impairment, depression and anxiety in an urban elderly community. Br. J. Psychiatry 155, 317-329.

Livingstone, G., Hawkins, A., Graham, N., Blizard, B. and Mann, A. (1990) The Gospel Oak study: prevalence rates of demen- tia, depression and activity limitation among elderly residents in inner London. Psychol. Med. 20, 137- 146.

Murrell, S.A., Himmelfarb, S. and Wright, K. (1983) Prevalence of depression and its correlates in older adults. Am. J. Epidem. 117, 173-185.

Newman, J.P. (1989) Aging and depression. Psychol. Aging 4, 150-165.

Pearlin, L.J. and Schooler, C. (1978) The structure of coping. J. Health Soc. Beh. 19, 2-21.

Radloff, L.S. (1977) The CES-D scale: a self-report depression

scale for research in the general population. Appl. Psychol. Meas. 1, 385-401.

Radloff, L.S. and Teri, L. (1986) Use of the CES-D with older adults. Clin. Gerontol. 5, 119-36.

Robins, L., Helzer, J.E., Croughan, J. and Radcliff, K.S. (1991) National Institute of Mental Health Diagnostic Interview Schedule: its history, characteristics and validity. Arch. Gen. Psychiatry 38, 381-389.

Romaniuk, M., Mc Auley, W.J. and Arling, G. (1983) An exami- nation of the prevalence of mental disorders among the elderly in the community. J. Abn. Psychol. 92, 458-467.

Smit, J.H. and de Vries, M.Z. (1994) Procedures and results of the field work. In: Autonomy and Well-Being in the Aging Popu- lation: Report from the Longitudinal Aging Study Amsterdam 1992-1993. Free University Press, Amsterdam, The Nether- lands, pp. 7-1 3.

van Sonsbeek, J.L.A. (1988) Methodological and substantial as- pects of the OECD indicator of chronic functional limitations. Maandbericht Gezondheid (CBS) 88, 4-17.

van Tilburg, T.G., Dijkstra, P.A., Broese van Groenou, M.I. and Knipscheer, C.P.M. (1992) The primary social network in the NESTOR program Living arrangements and social networks of older adults. Free University, Amsterdam, The Netherlands.

Weissman, M.M. and Myers, J.K. (1978) Affective disorders in a US urban community. Arch. Gen. Psychiatry 35, 1304- 13 1 1.

Weissman, M.M., Leaf, P.J., Tischler, G.L., Blazer, D.G., Karno, M., Livingston, B.M. and Florio, L.P. (1988) Affective disor- ders in five United States communities. Psychol. Med. 18, 141-153.

Wells, K.B., Stewart, A. and Hays, R.D. (1989) The functioning and well-being of depressed patients: results from the Medical Outcomes Study. JAMA 262, 91 4-9 19.