Copyright 1991 by the Am

Journal of Abnormal Psycholo 1991, Vol. 100, No. 4,555-561

;an Psychological Association. Inc. 0021-84 3X/91/M.OO

Generation of Stress in the Course of Unipolar Depression Constance Hammen

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University of California, Los Angeles

The effect of stressful events on depression has been amply demonstrated, but the opposite relation is also important. I examined event occurrence over 1 year in 14 women with unipolar depression who were compared with demographically matched groups of women with bipolar disorder (n = 11), chronic medical illness (n- 13), or no illness or disorder (n = 22). Interview assessmentsof life events, severity, and independence of occurrence confirmed the hypothesis that unipolar women were exposed to more stress than the normal women, had significantly more interpersonal event stress than all others, and tended to have more dependent events than the others. The implication is that unipolar women by their symptoms, behaviors, characteristics, and social context generate stressful conditions, primarily interpersonal, that have the potential for contributing to the cycle of symptoms and stress that create chronic or intermittent depression.

subsequent depressive symptoms has been established in well-

Investigations of the relation of stress and depression have emphasized one direction of effect, the causal effect of events on symptoms. Stressors have been shown to predict subsequent depressive symptomatology in patients as well as community residents and may account for a significant portion of the variance in symptoms and for trigger relapses (e.g., Billings & Moos, 1984; Brown & Harris, 1978; Lewinsohn, Hoberman, & Rosenbaum, 1988; Swindle, Cronkite, & Moos, 1989; Thoits, 1983). The opposite direction of causality, the effects of the de-

controlled studies, it is time to investigate the other direction of causality. Indeed, it is proposed that at least some subsets of depressed people are exposed to considerable stress by virtue of their condition and their characteristics and behaviors and that to some degree, depressed persons generate the stressors that befall them. It is important to address the gap in the empirical literature on the link between depression and the generation of stressful

pressed person on stress occurrence, has often been hypothesized (e.g., Coyne, Burchill, & Stiles, 1990; Depue & Monroe,

events. A valid model of clinical depression needs to take into

1986), but it has commonly been viewed as a methodological

1989) and the likelihood of its chronicity or recurrence (e.g.,

nuisance that confounds the test ofthestress-depression causal-

Hammen, 1991b). Such a model must consider the depressed

account the impairment that depression causes (Wells et al.,

ity (Depue & Monroe, 1986; Dohrenwend & Dohrenwend, 1981). Indeed, controlling for the confounding effects of prior symptoms is vitally important to demonstrating a relation between stressful events and depressive outcomes, and it is necessary to improve methods of data collection to obtain accurate information about events rather than potentially biased reports. Also, it has been theoretically and empirically critical to demon-

person in context, including environmental, historical, and temporal features of the course of disorder. The chronicity, or recurrence, of unipolar depression and the impairment of functioning associated with it suggest one way of viewing the reliable relation between past depression and future depression. I argue that depressed persons shape their environments, as well as respond to them, and the consequences of

strate the role that independent, or fateful, events have on sub-

their depression and behaviors may serve to generate stressful

sequent symptoms (e.g., Shrout et al., 1989). Nevertheless, such methodological and theoretical refinements leave researchers in the dubious position of ignoring two of the major correlates

conditions and events, which in turn cause additional symptomatology. Thus, the first hypothesis to be tested is that persons with histories of recurrent depression are exposed to higher

of depression. The overwhelming predictor of future depres-

levels of stressful life events than are comparison groups, be-

sion is past depression (e.g., Hammen, Mayol, deMayo, &

cause of the excess of events for which they are at least partly the cause.

Marks, 1986; Lewinsohn, Zeiss, & Duncan, 1989), and negative social or interpersonal events, which by definition typically in-

Second, I predict that the specific domain of stress generation in recurrent depressives is interpersonal. Recent empirical

volve some behaviors on the part of the subject, are potent predictors of depression (e.g. Brown & Harris, 1978; Hammen, Ellicott, Gitlin, & Jamison, 1989; Hammen, Marks, Mayol, &

and conceptual contributions by depression researchers have

deMayo, 1985; Paykel, 1979). Now that the association between negative life events and

emphasized the interpersonal difficulties experienced by depressed persons (e.g., Barnett & Gotlib, 1988; Coyne et al, 1990; Coyne, Kahn, & Gotlib, 1987; Coyne, Kessler et al., 1987). Research on the family context of depression, for instance, reveals an extraordinary array of interpersonal difficulties, such as the

The contributions of Dorli Burge, Cheri Adrian, David Gordon, Elizabeth Burnev and Jean Kaufman are gratefully acknowledged. Correspondence concerning this article should be addressed to Constance Hammen, Department of Psychology, University of California, Los Angeles, 401 Hilgard Avenue, Los Angeles, California 90024.

dysfunctional families of women with affective disorders, assortative mating involving marriages of depressed women to men with various psychiatric difficulties that are often followed by conflict and divorce, and maladaptive relationships of de-

555

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CONSTANCE HAMMEN

pressed women with their own children, who themselves display a variety of dysfunctions (reviewed in Hammen, 199la). Thus, there is ample reason to expect that the life event patterns of intermittently or chronically depressed people will involve more conflict and difficulty, attributable at least in part to the depressed person's symptoms, characteristics, behaviors, and milieu. A test of the stress generation perspective requires not only a longitudinal study with systematic evaluations of stress occur-

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rence and objective ratings of the impact and independence of events. Such a study also requires certain controls and comparisons. For instance, it is important to have demographically similar subjects to rule out the effects of differences in ecological conditions. Also, it is useful to include comparison groups to learn if the stress-generation effect is specific to unipolar depression or may also occur more generally in other chronically ill groups, both psychiatric and medical. In this investigation the occurrence of stressful life events over a 1-year longitudinal course, assessed with the contextual threat interview method at periodic intervals, was examined for a sample of unipolar depressed women patients with recurrent disorder. The unipolar depressed women were compared to normal, nonpsychiatric women, to women with bipolar illness, and to women with chronic medical conditions. The groups comprised demographically similar women who had children between the ages of 8 and 16.

Method Participants Four groups of women who were participants in the University of California, Los Angeles (UCLA) Family Stress Project, a study of children of women with affective and medical disorders, served as subjects. There were 14 women with unipolar depression, 11 with bipolar disorder, 13 with chronic medical illness (11 with insulin-dependent diabetes and 2 with rheumatoid arthritis), and 22 normal women. The 60 were a subset of the 68 women recruited into the Family Stress Project who completed at least 1 year of follow-up life stress evaluations (the other 8 did not complete the Year 1 follow-ups and were approximately equally distributed across the four groups). The reports of children's outcomes in this sample are presented in Hammen et al. (1987) and Hammen (1991a). The women had been recruited for a study of children's risk for psychopathology due to maternal illness. All of the subjects had to have at least one child between the ages of 8 and 16. The unipolar, bipolar, and medically ill women were all recruited from treatment resources, including UCLA Clinics and Hospitals, community agencies, and specialty private practices. Additional details of recruitment are reported in Hammen et al. (1987). The onset of the disorder for the three illness groups occurred before the child's birth or during the child's infancy. The unipolar women must have had more than one episode of major depression or have intermittent depression according to a Research Diagnostic Criteria (Spitzer, Endicott, & Robins, 1978) diagnosis, and by definition, the bipolar women had recurrent disorder. The unipolar and bipolar women and their families began the study no sooner than 3 months after admission to the hospital or to outpatient treatment, when the acute phase of a disorder had passed. The normal comparison women were recruited from the same, or demographically similar, schools as the children in the affective disorders groups, in an effort to match them for sociodemographic characteristics.

The demographic characteristics of the women in the four groups are reported in Table 1. The women did not differ on age, F(3, 56) = 1.25, p> .05, socioeconomic status (measured by Hollingshead's, 1975, two-factor index), F(3, 56) = 1.81, p > .05, or educational attainment, X2(3, N= 60) = 1.04, p> .05. The groups were mostly Caucasian with 20%-30% non-White, except for the medically ill women who were all White, x2(3, A"= 60) = 6.31, p= .098. The groups did, however, differ in marital status, with significantly more of the bipolar and unipolar women currently single, x2(3, N = 60) = 8.21, p = .04. Because the subjects were selected for the original Family Stress Project because they had children between the ages of 8 and 16, all the women had at least one such child, and the children in the study were equally distributed across groups by sex, \\3, N = 84) = . 13, p > .05, and by age, F(3, 80) = 2.41, p .05. The total number of children in the families did not differ, F(3, 56) = 1.80, p > .05. The unipolar and bipolar women had experienced multiple episodes of affective disorder (M = 12.4, SD = 8.6 for unipolar women and M= 7.6, SD = 5.7 for bipolar women; 5 of the unipolar women reported "too many depressive episodes to count," as did 1 bipolar woman). The unipolar women had been hospitalized for depression a mean of 2.1 times (SD = 2.2), and the bipolar women, 2.9 times (SD = 2.3). The medically ill women had also been hospitalized for their conditions a mean of 4.9 times (SD = 8.2). At the time of entrance into the study, the majority of women with affective disorders were still in treatment (86% of unipolar subjects and 100% of bipolar subjects). Most of the unipolar depressed and bipolar women received a combination of medication and psychotherapy (64% in each group). During the course of the 1-year follow-up, 11 of the 14 unipolar women had specific episodes of major depression, but 3 had no diagnosabledepression. Amongthel I bipolarwomen,2hadhypomaniaor mania alone, 4 had major depressive episodes alone, 1 had an minor depressive episode, 2 had both mania and major depression, and 2 had no diagnosable symptoms. Of the 13 medically ill women, 1 had a major depressive episode, 2 had minor depression, 1 had intermittent minor depressions, and the other 9 had no diagnosable depression. Among the normal women, only 1 had a minor depressive episode.

Procedure The initial assessment of the mothers included confirmatory diagnostic evaluations by the project staff, based on the Schedule for Affective Disorders and Schizophrenia (SADS; Endicott & Spitzer, 1979),

Table 1 Demographic Characteristics of Groups Group Measure

Age M SD No. children M SD Socioeconomic status category' M SD % with some college % White % currently married

Unipolar

Bipolar

Medical

Normal

38.1

37.5

40.5

37.3

5.3

6.2

3.4

4.6

1.6 0.8

2.2 1.6

1.8 1.3

2.5 1.1

2.6 1.2 79 79 29

2.0 0.9 82 91 46

1.8 0.7 92 100 69

2.1 1.0 82 68 73

• The lower the rating, the higher socioeconomic status.

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STRESS GENERATION modified slightly to yield diagnoses according to the Diagnostic and StatisticalManualof Mental Disorders (rev. 3rd ed.; American Psychiatric Association, 1987). The interviewers were advanced clinical psychology graduate students or psychologists on the project staff with extensive training in the SADS. During the initial phases of the study, a reliability analysis based on 32 cases yielded kappa coefficients of 1.00 for current and .92 for past diagnoses. The women were also interviewed every 6 months to determine psychiatric status since the last follow-up. After the initial evaluation sessions, the family members were contacted every 6 months for up to 3 years for follow-up assessment of life events and symptoms. We report life events for the 1st year combined over the two follow-ups. Interview-based collection of life stress data was considered to be preferable to questionnaire assessment, because of the insensitivity of such instruments to the personal significance of events and the occurrence of idiosyncratic events. Therefore, an interview schedule was developed, modeled after the contextual threat approach of Brown and Harris (1978). From an events list developed by Paykel and Mangen (1980) to remind subjects of various areas of content, the subjects were asked what events had occurred since the last interview (6 months before). The date and details of the event, including prior experiences with the event, available resources, and consequences, were obtained. This method places each event in the context in which it occurs. After the interview a narrative report was prepared for each event by the interviewer. The report contained contextual details, but specific information about how the informant felt about the event or how she reacted to it was omitted. Subsequent ratings of the stressfulness of events are therefore based on objective ratings by judges, rather than on subjective evaluations by the subjects themselves. Only negative events (those with at least mild threat ratings) were included. Objective threat ratings, on a 5-point scale from no threat (1) to severe threat (5), were given by an independent rating team (that did not include the interviewer). Ratings were given by the team for the magnitude of threat that would be likely to be experienced by a typical person under identical circumstances. Additionally, the team made independence ratings on a 5-point scale: 1 or 2 indicated that the event's occurrence was certainly or almost certainly independent of the behaviors and characteristics of the subject, 3 indicated that the event was possibly dependent or at least partly dependent on the behavior or characteristics of the subject, and 4 or 5 indicated that the event'soccurrence was almost certainly or certainly due to the behaviors or characteristics of the person. A reliability study of this rating method was conducted in a previous sample of outpatients and yielded interjudge correlations of .77 for objective threat and .85 for independence (ps < .0001), on the basis of 50 events rated by two teams. Additionally, all items that had been rated by the teams as dependent on the subject's behavior (ratings of 3,4, or 5) were subcategorized into those that were primarily interpersonal in content and those that were not. Two independent judges agreed 100% on this classification. The participants were interviewed every 6 months, so we combined events reported during both follow-ups in this study. The interviews were conducted by telephone, because of geographical and scheduling impracticalities that prevented face-to-face follow-up contacts. Interviewers were initially unaware of the woman's identity or group assignment. Similar methods have been used successfully in previous research with different samples of unipolar and bipolar outpatients and college students (e.g.. Ellicott, Hammen, Gitlin, Brown, & Jamison, 1990; Hammen, 1988; Hammen et al., 1989; Hammen et al., 1986).

Results Measures of Stressful Events The four groups were compared on four measures of stressful events: total, dependent, independent, and interpersonal stress-

557

ors (those dependent or possibly dependent events that often involved relationships with other people). Each of the measures comprised the total objective threat ratings assigned by the independent rating team for those events in a 1-year period. Separate analyses were also conducted on the number of events in each category, regardless of level of objective threat. It was predicted that the unipolar women would differ from normal women on all of the measures except for independent events. We also expected that unipolar women would differ from the bipolar women on all but independent events, given that their characteristics, such as different courses of disorder and differences in etiological variables, appear to differ from those of unipolar women. Because the medically ill women were expected to have elevated rates of medical events (rated as independent), they were not expected to differ from the unipolar women on total stress but were expected to differ on dependent events and interpersonal events. Table 2 displays the objective stress totals and event frequencies for each subtype of event by group. Planned comparisons were conducted because specific directional predictions were made. Planned comparisons between unipolar women and each of the other groups on total stress ratings indicated the expected significant difference from normal women, t(56) = 1.75, p < .05, one-tailed, but no significant difference between unipolar and medically ill women, 1(56) = 0.30, or bipolar women, /(56) = 1.06, p > .05. Similar results were observed for the total number of events, except for a borderline significant difference between the unipolar and normal groups, ;(56) = 1.49, p = .07, with similar rates for the unipolar and medical groups. Total stress scores comprised independent and dependent subscores. For the independent stress total, the planned comparisons showed no significant differences between the groups (p > .05), as predicted, although as expected, the medically ill women had the highest amount of such fateful stress impact because of their own medical difficulties and those of family members. Similarly, the number of independent events was comparable across groups, except for the highest frequencies for the medically ill women. Total impact ratings of dependent events were significantly higher for the unipolar women than for the normal women as predicted, /(56) = 2.67, p < .01, one-tailed. However, they were only marginally higher than the scores for bipolar, t(56) - 1.35, and medically ill women, r(56) = 1.58, ps > .05 < .10, onetailed. The frequency of dependent events showed similar patterns: The unipolar women had the highest mean (3.4), which differed significantly from the normal womenls mean (1.6), f(56) = 2.35, p < .01. They also differed significantly from the medically ill women, t(56) •= 1.66, p = .05, and marginally from the bipolar women, f(56) = 1.49, p = .07. Dependent events can be further subdivided into those that are interpersonal and those that are not (e.g., events that involve certain work circumstances, such as getting fired, that are caused at least in part by the person but are not predominantly interpersonal). It was predicted that the unipolar women would show more interpersonal event stress than all other groups, and planned comparisons confirmed that there were significantly higher rates for unipolar women than normal, «(56) = 2.76, p < .004, bipolar, /(56) = 1.67, p = .05, and medically ill women,

558

CONSTANCE HAMMEN Table 2 Mean Objective Threat Rating Totals and Event Frequency by Group Event Group and measure

Total

Independent

Dependent

Interpersonal

12.7 12.5

3.6 3.2

8.8 9.6

6.3 7.0

4.8 4.3

1.4 1.3

3.4 3.2

2.2 2.2

9.1 6.0

3.6 2.7

5.5 4.8

3.2 3.2

3.6 2.4

1.5 1.3

2.1 1.7

1.2 1.1

11.6 6.5

6.6 6.1

5.1 5.5

3.0 4.3

4.8 2.8

2.8 2.5

2.0 2.0

1.2 1.5

7.6 7.6

4.4 5.9

3.3 3.7

2.0 2.8

3.2 3.1

1.8 2.4

1.6 1.8

0.9 1.2

Unipolar (n = 14) Objective threat

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M SD Event frequency M SD Bipolar (n = 1 1 ) Objective threat M SD Event frequency

M SD Medically ill (n = 13) Objective threat

M SD Event frequency

M SD Normal (n = 22) Objective threat M SD Event frequency

M SD

((56) = 1.90, p < .05. In termsof the frequencies of interpersonal dependent events, the mean for unipolar women (2.2) was significantly higher than for all other groups, p < .05.

Nature and Timing of Interpersonal Events Conflict events.

The types of events that fell into the cate-

gory of dependent interpersonal events were varied, including changes in relationships, persons moving in or out, and conflict. Because conflict situations were the most frequent of the dependent interpersonal events, a separate analysis was conducted on the total objective threat for such events by group.

sode of major depression, the timing of episodes and events was inspected. Timelines of episodes, which noted reported onset and recovery, were constructed for each unipolar woman. Then, each interpersonal dependent event was entered, if any. Among the 11 women with major depression episodes, only 4 events (13% of all such events for this group) occurred during episodes; 10 events (33%) occurred before the onset of an episode, and 16 events (53%) happened after an episode had resolved (although 1 woman with 5 events and 1 woman with 1 event that occurred after the major depression resolved continued to experience low-grade symptoms). One of the 11 women

pline, conflicts with the spouse or boyfriend, disruptions of

had no interpersonal dependent events (but had events of other types). Of 3 unipolar women who did not have major episodes during the 1-year follow-up, 2 had interpersonal dependent

friendships, or dispute with a teacher or boss. The hypothesis

events, and 1 did not. On balance, the timing of interpersonal

that the unipolar and combined other groups would differ was

events does not appear to indicate that most or even many occur during periods of significant symptoms. This does not

Examples included conflicts with the child over rules and disci-

tested. The effect was significant, f(58) = 2.05, p < .05, twotailed. Thus, it appears that conflict is one dimension in which the unipolar women differ in interpersonal events from the other groups. They may also differ in other kinds of situations, but the frequencies were not large enough to test. Timing of events and episodes. As noted in the Method section, many of the women, including 11 of 14 unipolar women, had significant episodes of affective disorder during the 1-year follow-up reported. In an effort to determine whether the interpersonal dependent events that particularly characterized the unipolar group occurred because of (or at least during) an epi-

rule out the possibility, however, that undiagnosable chronic dysphoria can contribute to negative interpersonal events. Marital status. Because the unipolar and bipolar women were less likely to be currently married, it is possible that simply the status of being single, rather than mood disorder as such, contributes to more stressful interpersonal events. This is a difficult question because depression status and marital status are overlapping; for many depressed women, being married means high levels of conflict and break-up, whereas being single is also associated with stressful experiences. One way to approach this

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STRESS GENERATION

question is to compare stressors in married and nonmarried women in the sample, and the interaction of marital status and group. In order to examine the four categories of stress, analyses of variance were conducted on variables of current marital status and subject group. None of the variables showed statistically significant marital status effects or an interaction of marital status and subject group. In general, all variables except independent event threat suggested higher levels of stress for the single women, but the effect was not statistically significant. For example, the mean objective threat total was 11.7 for unmarried women and 8.6 forcurrently married women (p> .05). Also, for several of the single women, they were actually separated but experiencing conflict with the husband, so that marital events occurred to both the single (separated and divorced) and currently married women. In comparing the married (n = 4) and single (ft = 10) unipolar women, there were no significant differences on any of the stress variables, including interpersonal stress. For instance, the number of interpersonal events did not differ between the single (M = 2.9, SD = 2.6) and married (M= 1.3, SD = 0.5) women,/(12)= 1.23, p = .24, nor did total objective threat ratings differ significantly (M = 14.6, SD - 14.3 for unmarried and M = 8.0, SD = 4.3 for married women), 1(12) < 1, ns. Thus, there is no evidence that marital status is itself a significant contributor to the patterns of stress observed. Note, however, that the analyses must be interpreted cautiously because of the small numbers, which reduce the likelihood of detecting differences. Discussion These results of a 1 -year longitudinal study of the occurrence of life stressors confirm the general prediction that women with recurrent unipolar depression are exposed to more stress than normal women because of their higher rates of events to which they contributed rather than because of independent or fateful events. Moreover, even compared with bipolar and medically ill women who also experienced chronic illness conditions, the unipolar women tended to have more of the dependent events (those to which they contributed) and were significantly more likely than any other group to show negative interpersonal events to which they had contributed. The results were obtained both for frequencies of the types of events, as well as for total threat ratings by the objective rating team. It is important to emphasize that stress generation does not simply imply that women have defective personalities that cause events. Although depressed women's symptoms and characteristics may contribute to event occurrence, such women also find themselves in unstable social circumstances and highrisk situations in which certain stressors may be likely to occur. Thus, a complex mix of personal characteristics and context factors contribute to event occurrence. As examples of events that occur in the lives of depressed women, consider the following actual vignettes, selected to illustrate the differences between groups in a 1-year period (potentially identifying features have been altered). A woman with unipolar depression had a car accident in which her knee was injured, failed a civil service exam that would have opened job opportunities, moved out of her home after conflict with her husband, had a serious argument with her daughter who re-

559

mained with the father, divorced the husband, and got into a fight with her ex-husband over her new boyfriend. Also during the year her grandmother, to whom she had been close, died. A bipolar woman, by contrast, also had highly stressful events but fewer related to her behavior: She had a serious ear infection; her car was stolen; she got laid off due to economic conditions, was the victim of a hit and run accident, and ended a relationship with a man. A medically ill woman's son had a car accident, her daughter suffered severe headaches and had to be tested and put on medication, her husband retired, which caused financial strains, her son went away to college, and she had eye surgery for complications of her illness. Finally, a typical woman in the normal group had a minor accident in the home, and her father-in-law died. These vignettes indicate that women with unipolar depression had both high rates of events and high impact events; many involved interpersonal relationships, especially conflict. The bipolar women tended not to differ from the medical and normal groups in general, whereas the medically ill women had fairly high rates of independent events that reflected illness and injury to themselves and others. The normal group women had relatively low frequencies of events with relatively low impact. The overall results were not accounted for by differences in divorce rates of the affective disorders groups. A larger sample would be necessary to more fully explore this issue, but one may speculate that although being a single parent itself is highly stressful, unipolar depressed women in general may also have stressful relationships and marriages. Similarly, the timing of women's depressive episodes did not appear to account for the increased rates of interpersonal events in the unipolar groups. The majority of such events for these women occurred before a major depressive episode or after the recovery from such an episode. Although low-grade dysphoria cannot be ruled out as a contributor to event occurrence, it is also likely that characteristics of the women, their beliefs and skills for interpersonal relationships, contribute to event occurrence. Although in some ways the results of the comparisons of these groups are unsurprising, many implications and speculations follow. The observed patterns suggest a perspective for understanding some forms of recurrent or chronic depression: Persons contribute to the stream of events that provoke further depression and a sense of personal depletion and inefficacy. Negative cognitions about themselves and events may alter their responses to circumstances or may contribute to an inability to cope with emergent situations, and they may also determine reactions to personally meaningful events. In a sense, therefore, depression causes future depression through the mediation of stressors and cognitions about the self and circumstances. There are numerous questions about stress reactivity and depression to be explored. Is there differential biological or psychological reactivity to stress, given that some people obviously do not become depressed for long even after major negative events? Do stress-depression processes change over time? What are the behaviors and characteristics of the person that create stressful conditions or cause the absence of effective coping in the face of incipient stress? One recent model posits the process of neurochemical sensitization to stressors and suggests neurobiological alterations of the brain that alter the threshold of reactivity over time (Gold, Goodwin, & Chrousos, 1988). Not

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560

CONSTANCE HAMMEN

only biological stress reactivity but also psychososocial coping and problem-solving skills and cognitions need to be studied to learn what it is about the depressed person that interferes with learning or executing adaptive responses to stress. Both internal (cognitive and skill) and external (resource) variables are part of the complex process of generating and coping with stressors over time. In this regard, studies of depressed children or children at risk for depression, assortative mating in persons with affective disorders, and various other interpersonal aspects of depression will help to clarify the stress-generation process. A further clinical implication is the apparent compatibility of the stress-generation hypothesis with the descriptions of the putative neurotic depressive. Zimmerman, Coryell, Stangl, and Pfohl (1987) and Winokur (1985) have described a nonendogenous type of depressive characterized by high levels of adverse life events and marital conflict, early age at onset, and personality disorder. Further work is needed to characterize the qualities of such persons and the characteristics of the course of depression in those particularly marked by patterns of stress causation. Certainly, early age of onset and history of parental psychopathology may dispose a person to disruptions of skill acquisition. Recently, Hammen, Davila, Brown, Ellicott, and Gitlin (in press) studied severity of depression in a longitudinal study of unipolar outpatients. Early age of onset and parental psychopathology predicted the severity of episodes, through the mediation of chronic and episodic stressors. Thus, stress contributes to symptoms, but the stress itself may have an origin in the early experiences and skills of the person. The emphasis on the generation of interpersonal stress is scarcely surprising to those who have long emphasized the interpersonal aspects of depression (e.g., Peter M. Lewinsohn, James C. Coyne, Ian H. Gotlib, George W Brown, or Eugene S. Paykel). The observed pattern confirms the need to understand the depressed person in context, the familial, environmental, and temporal-historical context (e.g., Hammen, in press). That is, no amount of elegant examination of neurotransmitters or laboratory analogues of problem-solving, cognitions, or crosssectional life events can capture the complexities of the prediction of depression. At the same time, each of these and other elements need to be explicated for their contribution to overall models of types of depression. This study represents only an initial step and is limited by the small sample sizes. Also, there is the possibility that the results cannot be generalized to other groups of depressed persons, such as those who do not have children (or dysfunctional children), or men, or those who do not experience recurring depression, or those without family histories of psychopathology. The unipolar women in this sample were selected for recurrent depression, although increasingly research suggests that for many people who do experience major depression, it will go on to become a recurrent depression (see review in Hammen, 1991 b). The women in this study had a high rate of 1 -year recurrence or relapse of major depression and therefore represent a rather severely affected population of unipolar depressed people. Other samples need to be studied to explore the generality of the present effects. On the other hand, the bipolar group represents a comparison for recurrent disorder, and the medically ill group represented a comparison for chronic stressful conditions. The fact that the unipolar group differed from them im-

plies something specific and unique about them, although at this point one can only speculate. As a further limitation, the assessment of stress relied on contextual threat interviews conducted by telephone. There is no reason to expect systematic misrepresentation by unipolar depressed women, as compared with other groups, in such methods, and the contextual threat interview procedures provide extensive information as compared with questionnaires. Nevertheless, the possibility that unipolar depressed women are biased in their recall and reporting of interpersonal events is an empirical question that ought to be explored. Other methods of assessing stressful events, including reports by others or more objective sources, that may be used to explore the hypotheses of this study will be welcomed. Moreover, numerous questions about what it is that depressed people are doing that may contribute to stressful events remain to be addressed. The major goal of my work is to address the often-noted relation between depression status and ensuing events; the real challenge, to characterize the causes and implications of this pattern, lies ahead.

References American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (Rev. 3rd ed). Washington, DC: Author. Barnett, P. A, & Gotlib, I. H. (1988). Psychosocial functioning and depression: Distinguishing among antecedents, concomitants, and consequences. Psychological Bulletin, 104, 97-126. Billings, A. G., & Moos, R. H. (1984). Coping, stress, and social resources among adults with unipolar depression. Journal of Personality and Social Psychology, 46, 877-891. Brown, G. W, & Harris, T. (1978). Social origins of depression. London: Free Press. Coyne, J. C., Burchill, S, & Stiles, W (1990). An interactional perspective on depression. In C. R. Snyder & D. O. Forsyth (Eds), Handbook of social and clinical psychology: The health perspective (pp. 327349). New York: Pergamon Press. Coyne, J. C., Kahn, J, & Gotlib, I. H. (1987). Depression. In T. Jacob (Ed), Family interaction and psychotherapy (pp. 509-533). New York: Plenum Press. Coyne, J. C., Kessler, R. C, Tal, M., Turnbull, J., Wortman, C. B, & Greden, J. F. (1987). Living with a depressed person. Journal of Consulting anddinical Psychology, 55, 347-352. Depue,R.A.,&Monroe,S.M.(1986). Conceptualization and measurement of human disorder and life stress research: The problem of chronic disturbance. Psychological Bulletin, 99, 36-51. Dohrenwend, B. S, & Dohrenwend, B. P. (1981). Life stress and illness: Formulation of the issues. In B. S. Dohrenwend & B. P. Dohrenwend (Eds), Stressful life events and their contexts (pp. 1-27). New York: Prodist. Ellicott, A., Hammen, C, Gitlin, M., Brown, G, & Jamison, K. (1990). Life events and course of bipolar disorder. American Journal of Psychiatry, 147, 1194-1198. Endicott, J., & Spitzer, R., (1979). Use of Research Diagnostic Criteria and the Schedule for Affective Disorders and Schizophrenia to study affective disorders. American Journal of Psychiatry, 136, 52-56. Gold, P. W, Goodwin, F. K, & Chrousos, G. P. (1988). Clinical and biochemical manifestationsof depression: Relation to the neurobiology of stress. New England Journal of Medicine, 319, 413-420. Hammen, C. (1988). Self-cognitions, stressful events, and the prediction of depression in children of depressed mothers. Journal of Abnormal Child Psychology, 16, 347-360.

561

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STRESS GENERATION

Hammen, C. (199 la). Depression runs in families: The social context of risk and resilience in children of depressed women. New York:

sive disorder. In R. A. Depue (Ed.), The psychobiology of the depressive disorders: Implications forthe effects oj'stress(pp. 245-262). New

Springer-Verlag. Hammen. C. (1991b). Mood disorders (unipolar depression). In M. Hersen&S. Turner (Eds), Adult psychopa/hology and diagnosis (2nd ed., pp. 170-207). New York: Wiley. Hammen, C. (in press). Psychological vulnerability to depression: A cognitive-environmental perspective. In B. Bloom & K. Schlesinger (Eds.), The First Boulder Symposium on Clinical Psychology: Depression. Hillsdalc, NJ: Erlhaum. Hammen, C, Adrian, C, Gordon, D., Burge, D., Jaenicke, C., & Hiroto, D. (1987). Children of depressed mothers: Maternal strain and symptom predictors of dysfunction. Journal of Abnormal Psychology, 96,190-198. Hammen, C, Davila, J, Brown, G., Ellicott, A., & Gitlin, M. (in press). Psychiatric history and stress: Predictors of severity of unipolar depression. Journal of Abnormal Psychology. Hammen, C., Ellicott, A., Gitlin, M., & Jamison, K. R. (1989). Sociotropy/autonomy and vulnerability to specific life events in unipolar and bipolar patients. Journal of Abnormal Psychology, 98,154-160. Hammen, C, Marks. T, Mayol, A.. & deMayo. R. (1985). Depressive self-schemas, life stress, and vulnerability to depression. Journal of Abnormal Psychology. 94, 308-319. Hammen, C., Mayol, A., deMayo, R., & Marks, T. (1986). Initial symptom levels and the life-event-depression relationship. Journal oj'Ab-

York: Academic Press. Paykel, E. S., & Mangen, S. P. (1980). Interview for recent life events. Unpublished manuscript, St. Georges Hospital Medical School, Uni-

normal Psychology. 95,114-122. Hollingshead, A. (1975). Four-factor index of social status. Unpublished manuscript, Yale University, New Haven, CT. Lewinsohn, P. M., Hoberman, H. M., & Rosenbaum, M. (1988). A prospective study of risk factors for unipolar depression. Journal of Abnormal Psychology, 97. 251-264. Lewinsohn, P. M., Zeiss, A. M., & Duncan, E. M. (1989). Probability of relapse after recovery from an episode of depression. Journal of Ab-

versity of London. Shrout, P. E., Link. B. G., Dohrenwend, B. P., Skodol, A. E., Stueve, A, & Mirotznik, J. (1989). Characterizing life events as risk factors for depression: The role of fateful loss events. Journal of Abnormal Psychology. 98. 460-467. Spitzer, R., Endicott, J., & Robins, E. (1978). Research DiagnosticCriteria: Rationale and reliability. Archives of General Psychiatry, 35,773-

782. Swindle, R. W, Cronkite, R. C., & Moos, R. H. (1989). Life stressors, social resources, coping, and the 4-year course of unipolar depression. Journal of Abnormal Psychology, 98, 468-477. Thoits, R A. (1983). Dimensionsoflife events that influence psychological distress: An evaluation and synthesis of the literature. In H. B. Kaplan (Ed.), Psychosocial stress: Trends in theory and research (pp. 33-103). New York: Academic Press. Wells, K. B., Stewart, A., Hays, R. D., Burnam, M. A., Rogers, W, Daniels, M, Berry, S., Greenfield, S., & Ware, J. (1989). The functioning and well-being of depressed patients: Results from the Medical Outcomes Study. Journal of the American Medical Association, 262, 914-919. Winokur, G. (1985). The validity of neurotic-reactive depression. Archives of General Psychiatry, 42, 1116-1122. Zimmerman, M, Coryell, W, Stangl, D., & Pfohl, B. (1987). Validity of an operational definition for neurotic unipolar major depression. Journal of Affective Disorders, 12, 29-40.

normal Psychology. 98,107-116. Paykel, E. S. (1979). Recent life events in the development of the depres-

Received June 25,1990 Revision received January 14,1991 Accepted January 20,1991 •

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