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The role of life events in depression in primary medical care versus psychiatric settings
Journal of Affective Disorders 82 (2004) 353 – 361 www.elsevier.com/locate/jad
Research report
The role of life events in depression in primary medical care versus psychiatric settings James C. Coynea,*, Richard Thompsonb, Carolyn M. Pepperc a
Department of Psychiatry, University of Pennsylvania School of Medicine, 11 Gates/HUP, 3400 Spruce Street, Philadelphia, PA 19104-4283, United States b Juvenile Protective Association, United States c University of Wyoming, United States Received 2 December 2003; accepted 16 February 2004
Abstract Background: The relationship between negative life events and depression is inconsistent. The purpose of the current study is to investigate the hypothesis that depression in the community may be related more to major life events than is depression in psychiatric settings. Methods: This hypothesis was tested using depressed primary medical care (PC; n=70) and psychiatric patients (n=62). Nondistressed (n=109) and distressed/nondepressed PC patients (n=43) served as comparison-control groups. Life events were rated using the contextual method of Brown and Harris (Brown, G.W., Harris, T.O., 1978. Social origins of depression. Tavistock, London). Results: Depressed PC patients, but not depressed psychiatric patients, were significantly more likely to have recent severe events than the comparison-control groups. Self-reported distress in the absence of depression was not associated with severe life events. Limitations: History of depression was assessed using a simple count of number of previous episodes, and the assessment of depression history may require more sophisticated assessment. The measure of endogenous depression used in this study was created post-hoc and needs replication. Conclusions: Diathesis-stress models need to accommodate a lack of universality for severe stress prior to the onset of depression. Clinical strategies may need to reflect patient treatment preferences associated with differences across settings with respect to the perceived role of stress in their depression. D 2004 Elsevier B.V. All rights reserved. Keywords: Depression; Treatment settings; Life events; Primary care
* Corresponding author. Tel.: +1 215 662 7035; fax: +1 215 349 5067. E-mail address: [email protected] (J.C. Coyne). 0165-0327/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2004.02.008
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1. Introduction Psychological explanations of depression presume a crucial role for stressful life events. Sophisticated studies confirm severe life events often play a key role in the onset of depression (Brown and Harris, 1978; Kendler et al., 1993). However, a strong association between life events and depression has not always been found (Bebbington et al., 1981; Brown et al., 1994). Results tend to depend on the methodologies used to assess life events and depression, and the population studied (Coyne and Downey, 1991). The earliest studies found a modest relationship between life events and depression. However, these studies relied on checklist assessments of life events and self-report measures of distress, and problems inherent in relying exclusively on such self-report measures were subsequently identified (Coyne and Downey, 1991; Hammen et al., 1986). Endorsement of an item on a life events checklist is a poor indicator of the occurrence of a severe stressor (Brown and Harris, 1978), and an elevated score on a self-report measure of distress is a poor indicator of clinical depression (Coyne, 1994). One reason for the poor performance of checklist assessment of life events is that most items on the typical checklist do not tap severe life events, which are generally infrequent. Thus, elevated scores likely reflect the occurrence of mild to moderate events. Inclusion of less threatening events inflates tallies of recent life events without improving estimates of risk for depression (Coyne and Whiffen, 1995). A second reason for the poor performance of life event checklists is that individual items are bthin descriptionsQ (Geerwitz, 1973) of complex situations. Upon probing, many items reflect neither stressful circumstances nor discrete recent events (Brown and Harris, 1978). Two respondents’ endorsements of the same item may reflect considerable differences in the nature of the event. A promising alternative to checklists is semistructured interviews with probing and consideration of situational and personal factors that determine the level of threat posed by events (Brown and Harris, 1978). However, this methodology is labor-intensive, limiting its adoption as a standard, though evidence of its validity is compelling (Coyne and Downey, 1991). Questions remain about the generalizability of findings concerning the role of life events in
depression, even when appropriate methods are used. Brown et al. (1985) concluded that depression in the community did not differ from depression in a psychiatric sample in the frequency of recent adverse events. Yet, Bebbington et al. (1981) found that affective disorder was relatively independent of severe life events in psychiatric samples, but severity of depressive symptoms was proportional to the severity of life events in the community. Psychological distress in the absence of a major depression should be more strongly associated with mild and moderate stressors than with less frequently occurring severe life events (Coyne and Whiffen, 1995; Monroe and Simons, 1991). Elevated scores on self-report measures of distress are relatively common, with a third or more of primary care patients scoring above a standardized cutpoint (Fechner-Bates et al., 1994). It is not logical to use an infrequent antecedent such as a severe life event to explain commonly occurring condition. Formally, the strength of an association between two variables is limited by the similarity in their distributions (Carroll, 1961). Thus, on the basis of differences in their prevalence, one would not expect a strong relationship between distress and severe life events, once cases of major depression are excluded. These considerations suggest hypotheses about what would be found using a contextual assessment of life events in primary care and psychiatric samples. Depressed primary care patients are not typically seeking treatment for their depression in their index visit. They can be expected to be similar to depressed persons drawn from the community for whom an excess of recent severe life events is routinely found. More controversial is the prevalence of life events among depressed psychiatry patients. Brown and Harris’s (1982, 1989) data suggest that depressed patients, regardless of setting, are likely to have an excess of life events. In contrast, others (e.g., Bebbington et al., 1981) find no elevation in life events among depressed psychiatric patients. There are a number of possible explanations why depressed psychiatric patients might report fewer life events than depressed primary care patients. Endogenous depression may be less associated with severe life events than is nonendogenous depression (Brown et al., 1994). Post’s kindling theory (Post et al., 1992), that depressive episodes become increasingly independent
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of stressful life events with subsequent recurrences, may also be consistent with this perspective. Several studies found that life events are more strongly linked to first episodes of depression (e.g., Ezquiga Terrazas et al., 1987). The present study compared the role of life events in depression across two populations: primary medical care and a specialty depression program. A contextual assessment of life events (Brown and Harris, 1978) was used, and major depression was assessed using the Structured Clinical Interview for DSM-III-R (SCID; Spitzer et al., 1989) in both populations. Two comparison-control groups were also included: nondistressed primary care patients and an additional group of primary medical care patients who reported psychological distress, but who were not diagnosed as depressed in an interview with the SCID.
2. Method The data presented in this paper were collected as part of the Michigan Depression Project (MDP). The MDP explores the prevalence, nature, and detection by physicians of depressive disorders among primary medical care patients, as well as differences between these patients and depressed patients who present at a depression program based in a major medical center department of psychiatry (see Fechner-Bates et al., 1994). 2.1. Participants The depressed psychiatric group of consisted of 62 outpatients who met DSM-III-R (APA, 1987) criteria for major depressive disorder in a semi-structured interview. The depressed primary care group consisted of 70 patients who similarly met criteria for major depression. The nondistressed, nondepressed comparison group consisted of 109 primary care patients who scored below the standard cutpoint of 16 on the CESD and who failed to meet criteria for any depressive disorder according to DSM-III-R. The distressed, nondepressed comparison group consisted of 43 primary care patients who scored at or above the standard cutpoint of 16 on CES-D, but failed to meet criteria for major depressive disorder or dysthymia according to DSM-III-R. Patients who met criteria for
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bipolar disorder or dysthymia were excluded from these analyses. 2.2. Measures 2.2.1. Psychiatric diagnosis Diagnosis was made using the SCID (Spitzer et al., 1989). Interviewers were Masters or PhD level social workers or psychologists who completed 60 h of training on use of the SCID. Inter-rater agreement was 97% for ratings of symptom levels and 93% for diagnostic decisions. 2.2.2. Stressful life events Life events were assessed using a two-stage procedure (Costello and Devons, 1988). A screening for the occurrence of life events was first done using the Michigan Interview of Life Events (MILE), adapted from the Psychiatric Epidemiology Research Instrument (PERI; Dohrenwend et al., 1978). Endorsement of an item prompted the interviewer to undertake a semi-structured series of probes to determine the circumstances of the event. A committee of raters then rated the level of contextual threat, unaware of the diagnostic status of respondents. Ratings took into account only biographically relevant circumstances surrounding the event and how most people would react (Brown and Harris, 1978). Contextual assessment involves deliberately ignoring a respondent’s subjective impressions in order to address the question of bHow would a reasonable person react to such an event in such a set of circumstances?Q Level of threat was scored on a 4point scale similar to the Life Event and Difficulties Scale (LEDS) used by Brown and Harris, with 1 indicating most severe threat and 4 indicating an event associated with mild unpleasantness or anxiety. Level of threat experienced immediately after the event was rated as the short-term threat. Level of threat 2 weeks after the event was rated as the long-term threat. Given the variety of socioeconomic and cultural differences between England and North America, we adapted Brown and Harris’ rating system for the MDP, constructing a detailed dictionary of life events and documentation of factors affecting severity ratings. For a reliability study, trained raters, one of whom had been trained by Brown and Harris, scored the events of six participants, for a total of 24
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incidents. Agreement between the two groups of raters for distinguishing between an event versus an occurrence was high (j=0.80), and intraclass correlations between groups for threat ratings was 92.
in social roles and the bsevereQ category indicates several symptoms in excess of what was required for a diagnosis and marked interference in social roles. There was an intermediate bmoderateQ category.
2.2.3. Psychological distress The CES-D (Radloff, 1977) is a 20-item self-report instrument widely used as a measure of psychological distress. Hundreds of studies confirm the validity of the CES-D as an indicator of psychological distress. Most depressed persons score above the established cutpoint of 15, but most persons who score above this threshold are not clinically depressed (Fechner-Bates et al., 1994).
2.2.5. Impairment of functioning DSM-III-R Axis IV, the Global Assessment of Functioning Scale (GAF), involves an anchored 0–100 point assessment of psychological, social, and occupational functioning (APA, 1994). An interrater reliability study yielded an interclass correlation coefficient of 0.93 for agreement between two interviewers for their independent ratings of 19 audiotaped SCID interviews.
2.2.4. Severity of depression The Hamilton Depression Rating Scale (HDRS; Hamilton, 1960) is the most widely used intervieweradministered tool for the assessment of severity of depressive symptoms. We utilized the Structured Interview Guide for the HDRS (Williams, 1988). Consistent with the original design of the scale, we derived a total scale score based on 17 of the 21 items. Inter-rater reliability for the HDRS was determined using a rescoring of audiotapes, and the interclass correlation between raters was found to be 0.89. The SCID provides an additional measure of severity of major depression using DSM-III-R criteria. The category bmildQ designates patients with few symptoms in excess of diagnosis cutpoints and minor impairment
3. Results One-way ANOVAs with Tukey HSDs post-hoc tests and v 2 were used to assess differences between the four groups: Depressed psychiatric patients (n=62); depressed primary care (PC) patients (n=70); distressed/ nondepressed PC patients (n=43); and nondistressed PC patients (n=109). 3.1. Demographic and clinical variables Demographic and clinical information for the four groups are presented in Table 1. The groups did not differ on gender, but differed in age, F(3,280)=5.3, pb0.001, and level of education, F(3,280)=10.4,
Table 1 Demographic and clinical differences in psychiatry depressed, primary care depressed, primary care distressed and primary care nondistressed/ nondepressed patients
Sex (female) Age Education1 Ethnicity (Caucasian) Marital (currently married) CES-D total Hamilton score GAF Anxiety disorder Recurrent episode Number of previous episodes
Depressed psychiatric (n=62)
Depressed primary care (n=70)
PC nondepressed distressed (n=43)
Primary care nondistressed (n=109)
71.0% 34.8a 5.6a 90.3% 54.8%a 35.6a 13.7a 60.4a 29.0%a 80.6% 2.7
77.1% 38.9b 4.2b 99.1% 64.3%a,b 28.4b 12.8a 61.0a 31.4%a 80.0% 2.5
79.1% 39.1b 4.2b 95.3% 62.8%a,b 24.9b 7.4b 71.3b 23.3%a –
80.9% 43.2b 4.5b 95.7% 76.6%b 7.2c 3.1c 81.7bc 8.3%b –
CES-D=the Center for Epidemiologic Studies-Depression Scale (Radloff, 1977); GAF=Global Assessment of Functioning Scale. Row entries not sharing a common superscript differ at least at the pb0.05 level. 1 A score of 5 on the SCID rating corresponds to graduation from a 2-year college.
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pb0.001. The depressed psychiatric patients were significantly younger than the nondistressed PC patients, and significantly more educated than any of the other three groups. There was a trend toward fewer whites in the psychiatry depressed sample compared to the three PC care groups v 2 (3, n=284)=7.5, p=0.06, although all groups were at least 90% white. The PC nondistressed group was significantly more likely to be married than the psychiatry depressed group, v 2 (1, n=171)=7.5, pb0.01. The four groups differed in CES-D, F(3,265)=200.3, pb0.001, HDRS, F(3, 272)=75.7, pb0.001, and GAF scores, F(3,280)=73.67, pb0.001. The depressed psychiatric patients had significantly higher CES-D scores than the other three groups, while the nondistressed PC patients had significantly lower CES-D scores than the other three groups. Both depressed groups had significantly higher HDRS scores than the other two groups, while the nondistressed PC group had significantly lower HDRS scores than the other three groups. The PC nondistressed group had significantly higher GAF scores, indicating better functioning, than the other three groups. The PC distressed group also had significantly higher GAF scores than the two depressed groups. The nondistressed group had a lower prevalence of anxiety disorders than did the other three groups, which did not differ from each other in rates of anxiety disorders. The two depressed groups did not differ in the proportion of patients who were experiencing recurrent (rather than first-time) episodes of depression, or in the number of previous episodes experienced. About 80% of patients in each group were experiencing recurrent depression. The average number of previous episodes was between 2 and 3 for both groups, suggesting that the average patient was experiencing their third episode of depression. 3.2. Life events in depressed PC and psychiatric patients We used three different life event scores to compare the four groups, starting with the presence or absence of a severe life event, one high on long-term threat (Brown and Harris, 1978). Depressed PC patients were significantly more likely to have at least one severe life event than were the other three groups. Thoits (1983) proposed that the cumulative effect of life events is
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more closely tied to depression than the occurrence of a single event. To obtain a composite life events score, events were weighted by severity and summed. The depressed PC patients again had significantly higher weighted life events scores than did the other three groups, which did not differ with each other. The same pattern was found when the four groups were compared with respect to a simple sum of events. Although our results were consistent across various ways of quantifying stressful life events, two factors potentially limit interpretation of these results. First, the two depressed groups met criteria for a current diagnosis of major depression, but we did not distinguish those who may have had an onset of depression prior to the life event. Secondly, we included any events that had occurred within the last year, including those following onset of the depression. Depressed patients may be more likely to experience, and possibly generate, life events of an interpersonal nature while they are depressed (Hammen, 1991). To determine whether events precede the onset of depression, we reanalyzed the data looking only at patients with onsets of depression occurring in the past year. The presence of a severe event was examined for the 6 months prior to the onset of the depression. The resulting groups included 55 psychiatry patients with an onset of major depression in the past year, and 61 PC patients with an onset in the past year. There was no difference between the two groups in the proportion of patients experiencing an onset in the past year. In spite of the reduced statistical power, the results were similar to the larger sample: Depressed PC patients had more events than depressed psychiatric patients in the 6 months prior to onset of their depression, using both a simple sum of events, t(114)=4.0, pb0.005 and weighted event scores, t(101)=4.60, pb0.005, as well as a greater proportion with at least one severe event in the last 6 months, v 2 (1, n=116)=6.52, pb0.05. We also compared the proportions of health events in the psychiatric and PC depressed groups and found no differences. 3.3. Life events among PC and psychiatric patients with recurrent depression Within the psychiatric sample, a trend suggested that severe life events were associated with two or fewer recurrences v 2 (1, n=62)=3.04, p=0.08, indicat-
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ing that later depressions may be less associated with events. Depressed psychiatric patients without severe life events in the last year reported earlier age of first onset than patients who had a severe life event in the last year t(12.57, n=62)=2.63, pb0.05. There were no relationships within the depressed PC sample (n=66), between presence of severe events, and either recurrences or age of onset of depression. 3.4. Severity of depression and life events among depressed PC and psychiatric patients Depressed PC patients were more likely than the depressed psychiatric patients to fall into the DSM-IIIR mild category (Schwenk et al., 1996). Eliminating mildly depressed cases, there were 39 depressed PC patients and 49 depressed psychiatric patients. Severe events continue to be associated with PC depression, v 2 (1, n=88)=9.21, pb0.005. For weighted events scores, PC depressed had higher scores t(58.03)=3.75, pb0.001. Analysis of a simple count of number of events followed the same pattern of more events in the PC depressed group, t(86)=3.39, pb0.001. Finally, these results held when controlling for CES-D and GAF scores. 3.5. Do differences in chronicity explain differences in life events? The two groups did not differ in proportion of patients who had onsets within the past year (74.2% of depressed psychiatric patients with onsets in past year compared to 84.3% of PC patients). Using only patients with onsets in the past year, the PC group was significantly more likely to have a stressful life event prior to the onset of the depressive episode v 2 (1, n=95)=9.4, pb0.002, and to have a severe life
event prior to the onset, v 2 (1, n=95)=12.1, pb0.001. Within the past year, there were differences in the timing of the onsets of depression. The Psychiatry group had a significantly longer time between onset of depression and the SCID interview (5.0 months) than the PC depressed group (3.5 months), t(103)=2.5, pb0.02. However, since life events were assessed for the full year prior to the interview, the earlier onsets of the Psychiatry group resulted in a shorter period for assessing life events. In an attempt to compensate for this discrepancy, the groups were compared for life events during the preceding 9, 6, and 3 months. The PC group continued to have more events than the psychiatry group, whether the preceding 9 months, v 2 (1, n=105)=5.6, pb0.02, or 6 months, v 2 (1, n=105) =8.1, pb0.005, were examined. They also had more severe events in the preceding 9, v 2 (1, n=105)=8.4, pb0.005, and 6 months, v 2 (1, n=105)=4.9, pb0.05. There were no differences between the groups on events in the 3 months prior to onset, but only 12 of 93 cases reported any event in this time period. 3.6. Endogenous symptoms We created a scale of endogenous symptoms using the following HDRS symptoms: anhedonia, diurnal variation, early morning wakening, psychomotor retardation or agitation, and significant anorexia, and found no differences between the depressed groups (Table 2).
4. Discussion Depressed patients in primary care reported more severe life events than did depressed patients in psychiatry settings and distressed and nondistressed PC control groups. Results held for simple sum and
Table 2 Life events in psychiatry depressed, primary care depressed, primary care distressed, and primary care nondistressed/nondepressed patients
Severe event Number of events Weighted event score Event 6 months before onset
Depressed psychiatric (n=62)
Depressed primary care (n=70)
PC nondepressed distressed (n=43)
Primary care nondistressed (n=109)
17.7% (11)a 2.3a 5.1a 20% (11)a
50.0% (35)b 3.6b 9.3b 50.8% (31)b
25.6% (11)a 2.5a 6.0a N/A
19.3% (21)a 2.1a 5.0a N/A
N/A=not applicable. Row entries not sharing a common superscript differ at least at the pb0.05 level.
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weighted totals, and the presence of at least one severe event; when we limited our focus to events occurring since the onset of the current episode of depression; to major depression of at least moderate severity; and to depression with an onset in the past year. Health events did not explain these differences. Few studies have utilized the contextual approach of Brown and Harris (1978) in North America, and none have made the specific comparisons made here. However, the proportion of depressed primary care and comparison-control patients with recent life events corresponds well to the proportions in the community for new cases of depression and noncases, respectively, in the Brown and Harris (1978, 1989) studies. The proportion of depressed psychiatric patients in the present study with a recent severe event corresponds well to the results of Bebbington et al. (1981), but is lower than was obtained with a psychiatric sample by Brown and Harris (1978). A possible interpretation of more recent life events in depressed primary care patients is that depression in nonpsychiatric settings may represent a bdistress reaction,Q whereas depression in a psychiatric treatment setting may fit more of a disease model. The consistent excess of life events among depressed versus distressed primary care patients, however, highlights the distinction between bdistress reaction,Q as employed by Bebbington et al., and the typical criterion of an elevated score on a self-report measure of distress. It has previously been proposed that severe major life events are related to major depression, but not to distress absent depression (Monroe and Simons, 1991; Coyne, 1994). Until now, this had not been tested comparing distress and depression in a single population. Although the results concerning the relationship between life stress and depression in two populations were clear cut, the source of these differences was less clear. Goldberg and Huxley (1992) postulated that selective filters determine differences between depressed psychiatric patients and the larger pool of depressed persons in the community. Education and past mental health treatment are two such filters. In our study, depressed psychiatric patients were more educated than were depressed PC patients, and all of the depressed psychiatric patients had previous mental health treatment, a significantly larger proportion than for depressed primary care patients (Schwenk et al.,
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1996). Clinical features are also important; depressed persons with a more severe course or a lack of response to initial treatment in the community may be more likely to make their way to a specialized, research-oriented psychiatric setting. The depressed PC patients were less depressed and had higher functioning than the depressed psychiatric patients, but these variables failed to explain the different role for life events in the two populations. However, measures of symptoms and functioning obtained at a single point in time are a poor indicator of overall severity of the course of a recurrent, episodic disorder. We examined rates of recurrent depression, but few depressed patients in either group were experiencing a first episode, and the groups did not differ in mean number of episodes, yielding low power in explorations of life events as antecedents of early episodes of depression. Yet, a simple count of past episodes of depression could be misleading as an overall indicator of severity. Whereas episodes of depression in community samples tend to resolve in weeks or few months (Kendler et al., 1997), they more typically require 6 months or more in psychiatric samples (Piccinelli and Wilkinson, 1994). As well, although we calculated reliability for diagnostic labels, we did not specifically assess the reliability of the number or duration of episodes. Such reliability analyses are difficult to conduct within the context of conventional interviews. Possibly, some of the lack of significant differences may reflect low reliability of assessment, rather than real lack of difference. We also found no relationship between non-endogenous depression and increased life events within either depressed group. However, our measure of endogenous symptoms was created post-hoc, and findings that recurrent episodes of endogenous depression are less associated with life events (Brown et al., 1994) suggest that further inquiry into differences in symptom profile is warranted. In any case, depressed patients in primary care are likely to be more representative of depression in the general population than subjects recruited from specialty settings (Coyne et al., 2002). Depressed psychiatric patients who did not have a major life event immediately antecedent to their current episode of depression had an earlier age of first onset. Early first onsets of depression are associated with a more severe course in clinical samples (Giles et al., 1989). Post et al. (1992) posited
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that, with repeated episodes, depression become increasingly independent of stressful life events. Yet it could be that what Post has construed as a progression may be partly a matter of individual differences in life course. Some depressed persons may have earlier first onsets and more frequent recurrences independent of life stress. Others may have a form of depression that is also recurrent, but is more tied to severe life events, and does not progress to relative autonomy from life stress. If there is validity to these speculations, there may be differences in severity of course suggested in earlier age of onset and likelihood of treatment in a tertiary setting, but not captured in a simple tally of number of previous episodes. Data reported elsewhere on a subsample of the patients from this study suggest that depressed psychiatric patients are experiencing a more severe form of the disorder. The depressed psychiatric patients reported greater sense of stigma and concerns about the effects of their condition on their relationships and greater fears of recurrence (Coyne et al., 1998). Our efforts to establish the source of the patterning in terms of clinical data were unsuccessful, but some important implications of these findings do not depend on resolution of this issue. Psychological research on depression and distress has been dominated by the assumption that they occur in persons facing a major life event with insufficient coping or psychological vulnerability. At the very least, the present results question the generality of this assumption. In the present sample, antecedent major life events characterized depressed primary care patients, but not distressed patients or depressed psychiatric patients. Furthermore, in terms of the role of severe life events, the findings suggest that distress is not an adequate analog for clinical depression. Stress or other psychological factors are not irrelevant to distress or to depression in psychiatric samples, however. According to interpersonal models of depression, regardless of how depression comes about, interpersonal relationships are crucial to its course and outcome (Coyne and Benazon, 2001). Our results also have implications for controversies concerning the continuity of distress and clinical depression. Until now, debate over the equivalence of self-reported distress and major depression (Coyne, 1994; Vredenberg et al., 1993) has centered on
whether self-reported distress and major depression have similar correlates. The present study suggests a different way of addressing the issue: examining differences associated with whether distress is in the context of major depression. Results are clear cut: in the absence of major depression, distressed primary care patients are no more likely than nondistressed patients to have a recent major life event.
Acknowledgements We thank Suzanne Fechner-Bates and Gina South for their role in collecting and scoring life events data, and Kim Clum for her guidance in the use of the LEDS. This research was supported by a National Institute of Mental Health Center Grant, MH 5212906, and Grant R01-MH4376.
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Hammen, C., Mayol, A., deMayo, R., Marks, T., 1986. Initial symptom levels and the life event-depression relationship. J. Abnorm. Psychology 95, 114 – 122. Kendler, K.S., Kessler, R.C., Neale, M.C., Heath, A.C., Eaves, L.J., 1993. The prediction of major depression in women: toward an integrated etiologic model. Am. J. Psychiatry 150, 1139 – 1148. Kendler, K.S., Walters, E.E., Kessler, R.C., 1997. The prediction of length of major depressive episodes: results from an epidemiological sample of female twins. Psychol. Med. 27, 107 – 117. Monroe, S.M., Simons, A.D., 1991. Diathesis-stress theories in the context of life stress research: implication for the depressive disorders. Psychol. Bull. 110, 406 – 425. Piccinelli, M., Wilkinson, G., 1994. Outcome of depression in psychiatric settings. Br. J. Psychiatry 164, 297 – 304. Post, R.M., Rubinow, D.R., Ballenger, J.C., 1992. Conditioning and sensitization in the longitudinal course of affective illness. Br. J. Psychiatry 149, 191 – 201. 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. Schwenk, T.L., Coyne, J.C., Fechner-Bates, S., 1996. Differences between detected and undetected depressed patients in primary care and depressed psychiatric patients. Gen. Hosp. Psych. 18, 407 – 415. Spitzer, R.L., Williams, J.B., Gibbon, M.B., 1989. Structured Clinical Interview for DSM-III-R. Biometrics Research Department, New York State Psychiatric Institute, New York. Thoits, P.A., 1983. Dimensions of life events that influence psychological distress: an evaluation and synthesis of the literature. In: Kaplan, H.B. (Ed.), Psychosocial Stress: Trends in Theory and Research. Academic Press, New York, pp. 33 – 103. Vredenberg, K., Flett, G.L., Krames, L., 1993. Analogue versus clinical depression: a critical reappraisal. Psychol. Bull. 113, 244 – 327. Williams, J.B., 1988. A structured interview guide for the Hamilton depression rating scale. Arch. Gen. Psychiatry 45, 742 – 747.
Research report
The role of life events in depression in primary medical care versus psychiatric settings James C. Coynea,*, Richard Thompsonb, Carolyn M. Pepperc a
Department of Psychiatry, University of Pennsylvania School of Medicine, 11 Gates/HUP, 3400 Spruce Street, Philadelphia, PA 19104-4283, United States b Juvenile Protective Association, United States c University of Wyoming, United States Received 2 December 2003; accepted 16 February 2004
Abstract Background: The relationship between negative life events and depression is inconsistent. The purpose of the current study is to investigate the hypothesis that depression in the community may be related more to major life events than is depression in psychiatric settings. Methods: This hypothesis was tested using depressed primary medical care (PC; n=70) and psychiatric patients (n=62). Nondistressed (n=109) and distressed/nondepressed PC patients (n=43) served as comparison-control groups. Life events were rated using the contextual method of Brown and Harris (Brown, G.W., Harris, T.O., 1978. Social origins of depression. Tavistock, London). Results: Depressed PC patients, but not depressed psychiatric patients, were significantly more likely to have recent severe events than the comparison-control groups. Self-reported distress in the absence of depression was not associated with severe life events. Limitations: History of depression was assessed using a simple count of number of previous episodes, and the assessment of depression history may require more sophisticated assessment. The measure of endogenous depression used in this study was created post-hoc and needs replication. Conclusions: Diathesis-stress models need to accommodate a lack of universality for severe stress prior to the onset of depression. Clinical strategies may need to reflect patient treatment preferences associated with differences across settings with respect to the perceived role of stress in their depression. D 2004 Elsevier B.V. All rights reserved. Keywords: Depression; Treatment settings; Life events; Primary care
* Corresponding author. Tel.: +1 215 662 7035; fax: +1 215 349 5067. E-mail address: [email protected] (J.C. Coyne). 0165-0327/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2004.02.008
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1. Introduction Psychological explanations of depression presume a crucial role for stressful life events. Sophisticated studies confirm severe life events often play a key role in the onset of depression (Brown and Harris, 1978; Kendler et al., 1993). However, a strong association between life events and depression has not always been found (Bebbington et al., 1981; Brown et al., 1994). Results tend to depend on the methodologies used to assess life events and depression, and the population studied (Coyne and Downey, 1991). The earliest studies found a modest relationship between life events and depression. However, these studies relied on checklist assessments of life events and self-report measures of distress, and problems inherent in relying exclusively on such self-report measures were subsequently identified (Coyne and Downey, 1991; Hammen et al., 1986). Endorsement of an item on a life events checklist is a poor indicator of the occurrence of a severe stressor (Brown and Harris, 1978), and an elevated score on a self-report measure of distress is a poor indicator of clinical depression (Coyne, 1994). One reason for the poor performance of checklist assessment of life events is that most items on the typical checklist do not tap severe life events, which are generally infrequent. Thus, elevated scores likely reflect the occurrence of mild to moderate events. Inclusion of less threatening events inflates tallies of recent life events without improving estimates of risk for depression (Coyne and Whiffen, 1995). A second reason for the poor performance of life event checklists is that individual items are bthin descriptionsQ (Geerwitz, 1973) of complex situations. Upon probing, many items reflect neither stressful circumstances nor discrete recent events (Brown and Harris, 1978). Two respondents’ endorsements of the same item may reflect considerable differences in the nature of the event. A promising alternative to checklists is semistructured interviews with probing and consideration of situational and personal factors that determine the level of threat posed by events (Brown and Harris, 1978). However, this methodology is labor-intensive, limiting its adoption as a standard, though evidence of its validity is compelling (Coyne and Downey, 1991). Questions remain about the generalizability of findings concerning the role of life events in
depression, even when appropriate methods are used. Brown et al. (1985) concluded that depression in the community did not differ from depression in a psychiatric sample in the frequency of recent adverse events. Yet, Bebbington et al. (1981) found that affective disorder was relatively independent of severe life events in psychiatric samples, but severity of depressive symptoms was proportional to the severity of life events in the community. Psychological distress in the absence of a major depression should be more strongly associated with mild and moderate stressors than with less frequently occurring severe life events (Coyne and Whiffen, 1995; Monroe and Simons, 1991). Elevated scores on self-report measures of distress are relatively common, with a third or more of primary care patients scoring above a standardized cutpoint (Fechner-Bates et al., 1994). It is not logical to use an infrequent antecedent such as a severe life event to explain commonly occurring condition. Formally, the strength of an association between two variables is limited by the similarity in their distributions (Carroll, 1961). Thus, on the basis of differences in their prevalence, one would not expect a strong relationship between distress and severe life events, once cases of major depression are excluded. These considerations suggest hypotheses about what would be found using a contextual assessment of life events in primary care and psychiatric samples. Depressed primary care patients are not typically seeking treatment for their depression in their index visit. They can be expected to be similar to depressed persons drawn from the community for whom an excess of recent severe life events is routinely found. More controversial is the prevalence of life events among depressed psychiatry patients. Brown and Harris’s (1982, 1989) data suggest that depressed patients, regardless of setting, are likely to have an excess of life events. In contrast, others (e.g., Bebbington et al., 1981) find no elevation in life events among depressed psychiatric patients. There are a number of possible explanations why depressed psychiatric patients might report fewer life events than depressed primary care patients. Endogenous depression may be less associated with severe life events than is nonendogenous depression (Brown et al., 1994). Post’s kindling theory (Post et al., 1992), that depressive episodes become increasingly independent
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of stressful life events with subsequent recurrences, may also be consistent with this perspective. Several studies found that life events are more strongly linked to first episodes of depression (e.g., Ezquiga Terrazas et al., 1987). The present study compared the role of life events in depression across two populations: primary medical care and a specialty depression program. A contextual assessment of life events (Brown and Harris, 1978) was used, and major depression was assessed using the Structured Clinical Interview for DSM-III-R (SCID; Spitzer et al., 1989) in both populations. Two comparison-control groups were also included: nondistressed primary care patients and an additional group of primary medical care patients who reported psychological distress, but who were not diagnosed as depressed in an interview with the SCID.
2. Method The data presented in this paper were collected as part of the Michigan Depression Project (MDP). The MDP explores the prevalence, nature, and detection by physicians of depressive disorders among primary medical care patients, as well as differences between these patients and depressed patients who present at a depression program based in a major medical center department of psychiatry (see Fechner-Bates et al., 1994). 2.1. Participants The depressed psychiatric group of consisted of 62 outpatients who met DSM-III-R (APA, 1987) criteria for major depressive disorder in a semi-structured interview. The depressed primary care group consisted of 70 patients who similarly met criteria for major depression. The nondistressed, nondepressed comparison group consisted of 109 primary care patients who scored below the standard cutpoint of 16 on the CESD and who failed to meet criteria for any depressive disorder according to DSM-III-R. The distressed, nondepressed comparison group consisted of 43 primary care patients who scored at or above the standard cutpoint of 16 on CES-D, but failed to meet criteria for major depressive disorder or dysthymia according to DSM-III-R. Patients who met criteria for
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bipolar disorder or dysthymia were excluded from these analyses. 2.2. Measures 2.2.1. Psychiatric diagnosis Diagnosis was made using the SCID (Spitzer et al., 1989). Interviewers were Masters or PhD level social workers or psychologists who completed 60 h of training on use of the SCID. Inter-rater agreement was 97% for ratings of symptom levels and 93% for diagnostic decisions. 2.2.2. Stressful life events Life events were assessed using a two-stage procedure (Costello and Devons, 1988). A screening for the occurrence of life events was first done using the Michigan Interview of Life Events (MILE), adapted from the Psychiatric Epidemiology Research Instrument (PERI; Dohrenwend et al., 1978). Endorsement of an item prompted the interviewer to undertake a semi-structured series of probes to determine the circumstances of the event. A committee of raters then rated the level of contextual threat, unaware of the diagnostic status of respondents. Ratings took into account only biographically relevant circumstances surrounding the event and how most people would react (Brown and Harris, 1978). Contextual assessment involves deliberately ignoring a respondent’s subjective impressions in order to address the question of bHow would a reasonable person react to such an event in such a set of circumstances?Q Level of threat was scored on a 4point scale similar to the Life Event and Difficulties Scale (LEDS) used by Brown and Harris, with 1 indicating most severe threat and 4 indicating an event associated with mild unpleasantness or anxiety. Level of threat experienced immediately after the event was rated as the short-term threat. Level of threat 2 weeks after the event was rated as the long-term threat. Given the variety of socioeconomic and cultural differences between England and North America, we adapted Brown and Harris’ rating system for the MDP, constructing a detailed dictionary of life events and documentation of factors affecting severity ratings. For a reliability study, trained raters, one of whom had been trained by Brown and Harris, scored the events of six participants, for a total of 24
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incidents. Agreement between the two groups of raters for distinguishing between an event versus an occurrence was high (j=0.80), and intraclass correlations between groups for threat ratings was 92.
in social roles and the bsevereQ category indicates several symptoms in excess of what was required for a diagnosis and marked interference in social roles. There was an intermediate bmoderateQ category.
2.2.3. Psychological distress The CES-D (Radloff, 1977) is a 20-item self-report instrument widely used as a measure of psychological distress. Hundreds of studies confirm the validity of the CES-D as an indicator of psychological distress. Most depressed persons score above the established cutpoint of 15, but most persons who score above this threshold are not clinically depressed (Fechner-Bates et al., 1994).
2.2.5. Impairment of functioning DSM-III-R Axis IV, the Global Assessment of Functioning Scale (GAF), involves an anchored 0–100 point assessment of psychological, social, and occupational functioning (APA, 1994). An interrater reliability study yielded an interclass correlation coefficient of 0.93 for agreement between two interviewers for their independent ratings of 19 audiotaped SCID interviews.
2.2.4. Severity of depression The Hamilton Depression Rating Scale (HDRS; Hamilton, 1960) is the most widely used intervieweradministered tool for the assessment of severity of depressive symptoms. We utilized the Structured Interview Guide for the HDRS (Williams, 1988). Consistent with the original design of the scale, we derived a total scale score based on 17 of the 21 items. Inter-rater reliability for the HDRS was determined using a rescoring of audiotapes, and the interclass correlation between raters was found to be 0.89. The SCID provides an additional measure of severity of major depression using DSM-III-R criteria. The category bmildQ designates patients with few symptoms in excess of diagnosis cutpoints and minor impairment
3. Results One-way ANOVAs with Tukey HSDs post-hoc tests and v 2 were used to assess differences between the four groups: Depressed psychiatric patients (n=62); depressed primary care (PC) patients (n=70); distressed/ nondepressed PC patients (n=43); and nondistressed PC patients (n=109). 3.1. Demographic and clinical variables Demographic and clinical information for the four groups are presented in Table 1. The groups did not differ on gender, but differed in age, F(3,280)=5.3, pb0.001, and level of education, F(3,280)=10.4,
Table 1 Demographic and clinical differences in psychiatry depressed, primary care depressed, primary care distressed and primary care nondistressed/ nondepressed patients
Sex (female) Age Education1 Ethnicity (Caucasian) Marital (currently married) CES-D total Hamilton score GAF Anxiety disorder Recurrent episode Number of previous episodes
Depressed psychiatric (n=62)
Depressed primary care (n=70)
PC nondepressed distressed (n=43)
Primary care nondistressed (n=109)
71.0% 34.8a 5.6a 90.3% 54.8%a 35.6a 13.7a 60.4a 29.0%a 80.6% 2.7
77.1% 38.9b 4.2b 99.1% 64.3%a,b 28.4b 12.8a 61.0a 31.4%a 80.0% 2.5
79.1% 39.1b 4.2b 95.3% 62.8%a,b 24.9b 7.4b 71.3b 23.3%a –
80.9% 43.2b 4.5b 95.7% 76.6%b 7.2c 3.1c 81.7bc 8.3%b –
CES-D=the Center for Epidemiologic Studies-Depression Scale (Radloff, 1977); GAF=Global Assessment of Functioning Scale. Row entries not sharing a common superscript differ at least at the pb0.05 level. 1 A score of 5 on the SCID rating corresponds to graduation from a 2-year college.
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pb0.001. The depressed psychiatric patients were significantly younger than the nondistressed PC patients, and significantly more educated than any of the other three groups. There was a trend toward fewer whites in the psychiatry depressed sample compared to the three PC care groups v 2 (3, n=284)=7.5, p=0.06, although all groups were at least 90% white. The PC nondistressed group was significantly more likely to be married than the psychiatry depressed group, v 2 (1, n=171)=7.5, pb0.01. The four groups differed in CES-D, F(3,265)=200.3, pb0.001, HDRS, F(3, 272)=75.7, pb0.001, and GAF scores, F(3,280)=73.67, pb0.001. The depressed psychiatric patients had significantly higher CES-D scores than the other three groups, while the nondistressed PC patients had significantly lower CES-D scores than the other three groups. Both depressed groups had significantly higher HDRS scores than the other two groups, while the nondistressed PC group had significantly lower HDRS scores than the other three groups. The PC nondistressed group had significantly higher GAF scores, indicating better functioning, than the other three groups. The PC distressed group also had significantly higher GAF scores than the two depressed groups. The nondistressed group had a lower prevalence of anxiety disorders than did the other three groups, which did not differ from each other in rates of anxiety disorders. The two depressed groups did not differ in the proportion of patients who were experiencing recurrent (rather than first-time) episodes of depression, or in the number of previous episodes experienced. About 80% of patients in each group were experiencing recurrent depression. The average number of previous episodes was between 2 and 3 for both groups, suggesting that the average patient was experiencing their third episode of depression. 3.2. Life events in depressed PC and psychiatric patients We used three different life event scores to compare the four groups, starting with the presence or absence of a severe life event, one high on long-term threat (Brown and Harris, 1978). Depressed PC patients were significantly more likely to have at least one severe life event than were the other three groups. Thoits (1983) proposed that the cumulative effect of life events is
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more closely tied to depression than the occurrence of a single event. To obtain a composite life events score, events were weighted by severity and summed. The depressed PC patients again had significantly higher weighted life events scores than did the other three groups, which did not differ with each other. The same pattern was found when the four groups were compared with respect to a simple sum of events. Although our results were consistent across various ways of quantifying stressful life events, two factors potentially limit interpretation of these results. First, the two depressed groups met criteria for a current diagnosis of major depression, but we did not distinguish those who may have had an onset of depression prior to the life event. Secondly, we included any events that had occurred within the last year, including those following onset of the depression. Depressed patients may be more likely to experience, and possibly generate, life events of an interpersonal nature while they are depressed (Hammen, 1991). To determine whether events precede the onset of depression, we reanalyzed the data looking only at patients with onsets of depression occurring in the past year. The presence of a severe event was examined for the 6 months prior to the onset of the depression. The resulting groups included 55 psychiatry patients with an onset of major depression in the past year, and 61 PC patients with an onset in the past year. There was no difference between the two groups in the proportion of patients experiencing an onset in the past year. In spite of the reduced statistical power, the results were similar to the larger sample: Depressed PC patients had more events than depressed psychiatric patients in the 6 months prior to onset of their depression, using both a simple sum of events, t(114)=4.0, pb0.005 and weighted event scores, t(101)=4.60, pb0.005, as well as a greater proportion with at least one severe event in the last 6 months, v 2 (1, n=116)=6.52, pb0.05. We also compared the proportions of health events in the psychiatric and PC depressed groups and found no differences. 3.3. Life events among PC and psychiatric patients with recurrent depression Within the psychiatric sample, a trend suggested that severe life events were associated with two or fewer recurrences v 2 (1, n=62)=3.04, p=0.08, indicat-
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ing that later depressions may be less associated with events. Depressed psychiatric patients without severe life events in the last year reported earlier age of first onset than patients who had a severe life event in the last year t(12.57, n=62)=2.63, pb0.05. There were no relationships within the depressed PC sample (n=66), between presence of severe events, and either recurrences or age of onset of depression. 3.4. Severity of depression and life events among depressed PC and psychiatric patients Depressed PC patients were more likely than the depressed psychiatric patients to fall into the DSM-IIIR mild category (Schwenk et al., 1996). Eliminating mildly depressed cases, there were 39 depressed PC patients and 49 depressed psychiatric patients. Severe events continue to be associated with PC depression, v 2 (1, n=88)=9.21, pb0.005. For weighted events scores, PC depressed had higher scores t(58.03)=3.75, pb0.001. Analysis of a simple count of number of events followed the same pattern of more events in the PC depressed group, t(86)=3.39, pb0.001. Finally, these results held when controlling for CES-D and GAF scores. 3.5. Do differences in chronicity explain differences in life events? The two groups did not differ in proportion of patients who had onsets within the past year (74.2% of depressed psychiatric patients with onsets in past year compared to 84.3% of PC patients). Using only patients with onsets in the past year, the PC group was significantly more likely to have a stressful life event prior to the onset of the depressive episode v 2 (1, n=95)=9.4, pb0.002, and to have a severe life
event prior to the onset, v 2 (1, n=95)=12.1, pb0.001. Within the past year, there were differences in the timing of the onsets of depression. The Psychiatry group had a significantly longer time between onset of depression and the SCID interview (5.0 months) than the PC depressed group (3.5 months), t(103)=2.5, pb0.02. However, since life events were assessed for the full year prior to the interview, the earlier onsets of the Psychiatry group resulted in a shorter period for assessing life events. In an attempt to compensate for this discrepancy, the groups were compared for life events during the preceding 9, 6, and 3 months. The PC group continued to have more events than the psychiatry group, whether the preceding 9 months, v 2 (1, n=105)=5.6, pb0.02, or 6 months, v 2 (1, n=105) =8.1, pb0.005, were examined. They also had more severe events in the preceding 9, v 2 (1, n=105)=8.4, pb0.005, and 6 months, v 2 (1, n=105)=4.9, pb0.05. There were no differences between the groups on events in the 3 months prior to onset, but only 12 of 93 cases reported any event in this time period. 3.6. Endogenous symptoms We created a scale of endogenous symptoms using the following HDRS symptoms: anhedonia, diurnal variation, early morning wakening, psychomotor retardation or agitation, and significant anorexia, and found no differences between the depressed groups (Table 2).
4. Discussion Depressed patients in primary care reported more severe life events than did depressed patients in psychiatry settings and distressed and nondistressed PC control groups. Results held for simple sum and
Table 2 Life events in psychiatry depressed, primary care depressed, primary care distressed, and primary care nondistressed/nondepressed patients
Severe event Number of events Weighted event score Event 6 months before onset
Depressed psychiatric (n=62)
Depressed primary care (n=70)
PC nondepressed distressed (n=43)
Primary care nondistressed (n=109)
17.7% (11)a 2.3a 5.1a 20% (11)a
50.0% (35)b 3.6b 9.3b 50.8% (31)b
25.6% (11)a 2.5a 6.0a N/A
19.3% (21)a 2.1a 5.0a N/A
N/A=not applicable. Row entries not sharing a common superscript differ at least at the pb0.05 level.
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weighted totals, and the presence of at least one severe event; when we limited our focus to events occurring since the onset of the current episode of depression; to major depression of at least moderate severity; and to depression with an onset in the past year. Health events did not explain these differences. Few studies have utilized the contextual approach of Brown and Harris (1978) in North America, and none have made the specific comparisons made here. However, the proportion of depressed primary care and comparison-control patients with recent life events corresponds well to the proportions in the community for new cases of depression and noncases, respectively, in the Brown and Harris (1978, 1989) studies. The proportion of depressed psychiatric patients in the present study with a recent severe event corresponds well to the results of Bebbington et al. (1981), but is lower than was obtained with a psychiatric sample by Brown and Harris (1978). A possible interpretation of more recent life events in depressed primary care patients is that depression in nonpsychiatric settings may represent a bdistress reaction,Q whereas depression in a psychiatric treatment setting may fit more of a disease model. The consistent excess of life events among depressed versus distressed primary care patients, however, highlights the distinction between bdistress reaction,Q as employed by Bebbington et al., and the typical criterion of an elevated score on a self-report measure of distress. It has previously been proposed that severe major life events are related to major depression, but not to distress absent depression (Monroe and Simons, 1991; Coyne, 1994). Until now, this had not been tested comparing distress and depression in a single population. Although the results concerning the relationship between life stress and depression in two populations were clear cut, the source of these differences was less clear. Goldberg and Huxley (1992) postulated that selective filters determine differences between depressed psychiatric patients and the larger pool of depressed persons in the community. Education and past mental health treatment are two such filters. In our study, depressed psychiatric patients were more educated than were depressed PC patients, and all of the depressed psychiatric patients had previous mental health treatment, a significantly larger proportion than for depressed primary care patients (Schwenk et al.,
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1996). Clinical features are also important; depressed persons with a more severe course or a lack of response to initial treatment in the community may be more likely to make their way to a specialized, research-oriented psychiatric setting. The depressed PC patients were less depressed and had higher functioning than the depressed psychiatric patients, but these variables failed to explain the different role for life events in the two populations. However, measures of symptoms and functioning obtained at a single point in time are a poor indicator of overall severity of the course of a recurrent, episodic disorder. We examined rates of recurrent depression, but few depressed patients in either group were experiencing a first episode, and the groups did not differ in mean number of episodes, yielding low power in explorations of life events as antecedents of early episodes of depression. Yet, a simple count of past episodes of depression could be misleading as an overall indicator of severity. Whereas episodes of depression in community samples tend to resolve in weeks or few months (Kendler et al., 1997), they more typically require 6 months or more in psychiatric samples (Piccinelli and Wilkinson, 1994). As well, although we calculated reliability for diagnostic labels, we did not specifically assess the reliability of the number or duration of episodes. Such reliability analyses are difficult to conduct within the context of conventional interviews. Possibly, some of the lack of significant differences may reflect low reliability of assessment, rather than real lack of difference. We also found no relationship between non-endogenous depression and increased life events within either depressed group. However, our measure of endogenous symptoms was created post-hoc, and findings that recurrent episodes of endogenous depression are less associated with life events (Brown et al., 1994) suggest that further inquiry into differences in symptom profile is warranted. In any case, depressed patients in primary care are likely to be more representative of depression in the general population than subjects recruited from specialty settings (Coyne et al., 2002). Depressed psychiatric patients who did not have a major life event immediately antecedent to their current episode of depression had an earlier age of first onset. Early first onsets of depression are associated with a more severe course in clinical samples (Giles et al., 1989). Post et al. (1992) posited
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that, with repeated episodes, depression become increasingly independent of stressful life events. Yet it could be that what Post has construed as a progression may be partly a matter of individual differences in life course. Some depressed persons may have earlier first onsets and more frequent recurrences independent of life stress. Others may have a form of depression that is also recurrent, but is more tied to severe life events, and does not progress to relative autonomy from life stress. If there is validity to these speculations, there may be differences in severity of course suggested in earlier age of onset and likelihood of treatment in a tertiary setting, but not captured in a simple tally of number of previous episodes. Data reported elsewhere on a subsample of the patients from this study suggest that depressed psychiatric patients are experiencing a more severe form of the disorder. The depressed psychiatric patients reported greater sense of stigma and concerns about the effects of their condition on their relationships and greater fears of recurrence (Coyne et al., 1998). Our efforts to establish the source of the patterning in terms of clinical data were unsuccessful, but some important implications of these findings do not depend on resolution of this issue. Psychological research on depression and distress has been dominated by the assumption that they occur in persons facing a major life event with insufficient coping or psychological vulnerability. At the very least, the present results question the generality of this assumption. In the present sample, antecedent major life events characterized depressed primary care patients, but not distressed patients or depressed psychiatric patients. Furthermore, in terms of the role of severe life events, the findings suggest that distress is not an adequate analog for clinical depression. Stress or other psychological factors are not irrelevant to distress or to depression in psychiatric samples, however. According to interpersonal models of depression, regardless of how depression comes about, interpersonal relationships are crucial to its course and outcome (Coyne and Benazon, 2001). Our results also have implications for controversies concerning the continuity of distress and clinical depression. Until now, debate over the equivalence of self-reported distress and major depression (Coyne, 1994; Vredenberg et al., 1993) has centered on
whether self-reported distress and major depression have similar correlates. The present study suggests a different way of addressing the issue: examining differences associated with whether distress is in the context of major depression. Results are clear cut: in the absence of major depression, distressed primary care patients are no more likely than nondistressed patients to have a recent major life event.
Acknowledgements We thank Suzanne Fechner-Bates and Gina South for their role in collecting and scoring life events data, and Kim Clum for her guidance in the use of the LEDS. This research was supported by a National Institute of Mental Health Center Grant, MH 5212906, and Grant R01-MH4376.
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