Stress, social support and affective disorders in mothers of pre-school ...

Soc Psychiatry (1985) 20:100-105

Social Psychiatry 9 Springer-Verlag 1985

Stress, social support and affective disorders in mothers of pre-school children - a test of the stress-buffering effect of social support* Zahava Solomon Department of Mental Health Medical Corps, I. D. F., Israel

Summary. The study attempted to assess the stressbuffering role of social support using data from a survey of 436 mothers from two semi-rural regions of Pennsylvania. Results indicated that women with less adequate social support were more at risk for psychiatric disorder following the Three Mile Island nuclear accident. However, contrary to earlier reports, the role of social support as a stress moderator was not substantiated vis-&-vis affective disorder.

A consistent finding in social psychiatry has been the implication of stress in ill-health. Interestingly it has been observed that while many individuals react to stress maladaptively and develop illnesses, others may appear to be unaffected by it, A fundamental unanswered question is what accounts for this individual variability in response to apparently similar experiences? It was suggested that the noxious effects of stress may be modified or attenuated by social support (Antonovsky 1979; Cassel 1976; Liem and Liem 1978). A number of studies attempted to investigate the protective role of social support in psychiatric disturbances. The support provided by a confiding relationship appears to be salient in a number of studies (e.g. Lowenthal and Haven 1968). Similarly among women who experienced stressful life events, the development of the disturbance was related to the absence of a confiding relationship (Brown et al. 1975). Several community studies (Myers et al, 1975; Brown et al. 1977) indicated that, compared to less socially integrated individuals, the more socially in* This research was supported in part by N I M H contract no. 278-79-0048 (SM).

tegrated individuals reported fewer psychiatric symptoms when experiencing potentially stressful life events. Liem and Liem (1976), in a study of college students, reported that the higher proportion of people in one's network who provide emotional support, the lower the likelihood of reported feelings of depression and inadequacy. Further evidence of an independent effect of soical support on psychiatric status was provided by Andrews et al. (1978) and Miller and Ingham (1976). The protective role of social support regarding various disease entities for persons subjected to stress is not limited to psychiatric disturbances. The incidence rate of angina pectoris was found to be significantly lower among m e n who had a supportive wife ( Medalie and Goldbrout 1976). Another study (Gore 1973) investigated the health consequences of unemployment. Results indicated that men who had the emotional support of their wives during the period of unemployment experienced fewer symptoms of illness than those who lacked such support. Nuckolls et al. (1972) in a prospective study of women found that in the presence of high levels of life changes, women with high "psychosocial assets" (which consisted primarily of supportive relationships) had only one-third of the rate of complications of women of low psychological assets. Finally, Berkman and Syme (1979) conducted a 9-year follow-up study of a community sample. They found that respondents in the lowest support level had a relative risk of mortality of 2.3 for men and 2.8 for women. (This should be compared to the risk rate for respondents with high support level.) In sum, there is a considerable evidence for a link between social support and illness. This is particularly true in the case of affective disorders and especially among women. However, it is an open question (or "unclear") whether social support moderates the impact of stress or whether social support has an

101 Table 1. Background characteristics of sample T. M.I.

Beaver County

n

%

n

%

T. M. I. accident. The control group was composed of individuals who resided in Beaver County (western PA. U.S.A.). Beaver County was chosen as a comparison site for two reasons: 1. The nuclear reactors are also located in that area, and 2. The characteristics of the population are reasonably comparable to those of the T.M.I. group. Mothers of pre-school children were chosen to be subjects of the present investigation. This was done since they were believed to constitute a population at high risk for psychopathology for the following reasons"

Age

24 25-29 30+

74 132 106

23.8 42.4 33.8

28 47 49

22.6 37.9 39.5

Ethnic background

Caucasian Black other

301 7 4

96.5 2.2 1.3

121 2 1

97.6 1.6 0.8

Marital status

single married separated

4 305 3

1.3 97.8 1.0

0 123 1

0.0 99.2 0.8

Education

12 years some college college graduate or more

158 77 77

50.6 24.7 24.7

54 48 22

43.6 38.7 !7.7

1. Epidemiologic studies have suggested that recent mothers may have a higher rate of minor affective disorders than women without children.

Where grew up

same area elsewhere

188 124

60.3 39.7

86 38

69.4 30.6

Religion

Catholic Protestant other

86 205 21

27.6 65.7 6.7

54 59 11

43.5 47.6 8.9

2. Mothers of pre-school children were ordered to evacuate if they resided within a 5-mile radius of the plant.

5110

35.2

200 (2)

64.1 (0.7)

90 0

72.6 0.0

60 98 63 51 (40)

19.3 31.4 20.2 16.3 12.8

7 25 61 31 (3)

5.6 20.2 49.2 24.0 2.4

Employment employed outside status of the home housewife missing Total family income

14.999 15-19.999 20-24.999 25.999+ missing

34

27.4

effect on psychiatric status that is independent of stress. It appears that part of the problem in resolving this issue is related to the measure of stress typically used. In most of the above-mentioned studies where social support allegedly moderates stress, stressful life events checklists, which are highly confounded with social support measures, were employed (Mueller 1980). In assessing the moderating role of social support one has to ensure that the measures of social support one uses are indeed unrelated to the measures of stress. The present study was designed with this aim in mind.

Method

The present study is a part of a multi-cohort investigation of the mental health consequences of the Three Mile Island (T. M. I.) nuclear accident (Bromet et al. 1980). This study may be viewed as a natural experiment since the mental status of residents in the T. M. I. area (study group) was compared with that of comparable subjects who were not exposed to the

3. They were subjected to more waming than any other group in regard to possible radiation damage to their children. Furthermore, data collected shortly after the accident indicated that recent mothers experienced a great deal of distress (Dohrenwend et al. 1979). The sample consisted of 436 women. The T. M. I. group was composed of 312recent mothers and Beaver County numbered 124mothers. The sample was drawn from birth announcements that the local hospitals routinely transmit to the area newspapers. (A detailed description of the sampling procedure can be found in Bromet et al. 1980; Solomon and Bromet 1982.) Table 1 presents the demographic characteristics of the two groups of mothers. The median age was 27-28, with approximately two-thirds of the mothers under 30 years of age. Almost all the mothers were married (98%) and Caucasian (97%). Most of the women (80%) had one to two children. About half of the mothers in each area had formal education beyond high school. In both sites two-thirds had grown up in the same area in which they were currently living. There were some demographic characteristics on which the two groups of mothers differed. T.M.I. mothers were predominantly Protestant whereas in Beaver County Catholics and Protestants were equally represented. Relatively more mothers in the T. M.I. area were employed outside the home, although the total income appeared to be lower among T. M.I. mothers on the average. (However, 40% of the T.M.I. mothers did not answer the question about income, which may have influenced the findings on this variable.)

102 Thirty interviewers who had an advanced degree as well as clinical experience were trained to conduct the clinical interview. Respondents were randomly assigned to the interviewers. Data were gathered via a fully structured interview that was held on the first anniversary of the T.M.I. accident (March-April 1980). The interview contained questions regarding sociodemographic characteristics, life events, social support and mental health. The description that follows reflects only the variables pertinent for this study. 1. M e n t a l s t a t u s - Diagnosable affective disorders (depression and anxiety) as well as psychiatric symptomatology were assessed in the present study. A slightly modified version of the Schedule for Affective Disorders and Schizophrenia - Lifetime version (SAD-L) was used for determining psychiatric disorder classification using Research Diagnostic Criteria (Endicott and Spitzer 1978; Spitzer et al. 1978). Criteria for depression were: (i) a period of at least two weeks duration characterized by symptoms of depression, sadness, hopelessness, irritability or the like; (ii) seeking help from someone for these feelings, taking medication for the symptoms or acting differently with people during these times, and (iii) having at least one symptom such as sleep difficulties, fidgeting, excessive worrying, muscular tension or other related somatic problems. This analysis focused on episodes of depression and anxiety occurring during the year prior to interview (i. e. since the T. M. I. accident). For the assessment of subclinical levels of psychiattic disturbance the Symptom Checklist-90 (Derogatis 1977) was employed. This checklist inquires about symptoms during the two weeks preceding the interview. The items are rated on a five-point distress scale. The scale has been factor analyzed and nine symptom dimensions have been identified. In this report, the focus is on two symptom dimensions, namely depression and anxiety. S t r e s s - Exposure to the Three Mile Island (T. M.I.) accident was employed as the major measure of stress. The incident at the T. M. I. nuclear facility commenced on March 28, 1979. It entailed radiation leakages that lasted several days. In subsequent days it was seen as a potentially life-threatening event for many thousands of people. Unlike other disasters no lives were lost, no property was damaged and although 60% of the population in the area was evacuated, no one was subsequently relocated. Moreover, exacerbation of the initial stress continued through the study period. Specifically, it was a result of continuous radiation leaks and problems of decontaminating the plant. The T. M. I. acci-

dent represents an extreme situation that was unanticipated and beyond the control of the people exposed. Thus, the accident provided a measure of stress which was clearly independent of subjects' psychiatric status. social support measures were derived from a detailed Social Network Interview that was developed by Mueller and staff of the Psychiatric Epidemiology Program 1 at the University of Pittsburg. The schedule contains four sections dealing with support from the entire network, support provided by and reciprocated to an inner circle of five people, support from and to a confidant, and items regarding general availability of support from and to a confidant. In the present investigation two types of social support were assessed. These measures were based on answers each respondent gave to two specific questions that asked about expressive and instrumental support that she received from her network's members. Subsequently, an overall median for all subjects was attained and was used as a cut-off point. Thus, subjects scoring above the median were deemed to have high social support and subjects who scored below the median were judged to have low social support. 3. S o c i a l s u p p o r t - T h e

4. D a t a A n a l y s e s - T h e research question pertained to the stress - social support - disorder model. This is an antagonistic model of interaction. It postulates that social support decreases the pathogenic effect on the dependent variable. In statistical terms the model predicts a second order interaction. The interrelationships among three sets of variables, namely stress, social support and affective disorder, was examined. Using log linear modelling, each possible association of the three variables was assessed in terms of its contribution to the total variance. The most parsimonious model was considered the most acceptable.

2.

Results

The prevalence rates of depression and anxiety by site and by times of onset are presented in Table 2. Results indicate that rates of depression with onset prior to the T. M.I. accident are comparable in the two groups. However, after the T. M. I. accident the 1 Copiesof the Social NetworkInterviewand informationabout its psychometricpropertiesmay be obtained from Dr. E. Bromet, Departmentof Psychiatry,WesternPsychiatricInstitute and Clinic, 3811 O'Hara Street,Pittsburgh, Pa 15261,U.S.A.

103 Table2. Distribution of depression and anxiety by site and time of onset Outcome

Beaver County

T.M. 1.

n Major depression Definite major depression with onset after T. M. I. Probable major depression with onset after T. M. I. Major depression (probable and definite) with onset before T.M.I. Minor depression Minor depression with onset after T. M. I. Minor depression with onset before T. M. I. Generalized anxiety Anxiety with onset after T. M.I. Anxiety with onset before T. M.I.

%

n

%

22

7.1

4

3.2

7

2.2

2

1.6

97

31.1

36

29.0

4

1.3

0

0.0

16

5.1

10

8.0

14 16

4.5 5.2

1 2

0.8 1.6

Table3. Log-linear analysis of the relationship between mediating factors (A), stress (B) and affectivedisorder (C) (possible terms of association of these variables = AB, AC, BC, ABC) Psychiatric outcome

Vulnerability Log-likelihood ratio x~for factor separate parameters in equation AB

Definite major depression Definite and probable Major depression Generalized anxiety

Symptoms of depression

Symptoms of anxiety

Instrumental1.07 support Expressive 0.01 support Instrumental 1.18 support Expressive 0 . 0 0 support Instrumental 0.72 support Expressive 0.11 support Instrumental 1.35 support Expressive 0.00 support Instrumental 1.15 support Expressive 0 . 0 0 support

BC

AC

Model of best fit

ABC

2.91 0.05 1.92 A, B, C 2.86 0.94 2.14 A, B, C 3.13 0.62 2.26 A, B, C 2.95 4.71" 0.84

AC

4.68* 1.78 0.98 BC 5.01" 4.26* 0.61 7.26* 1.16

BC, AC 0.07 BC

6.95* 1.23 0.06 BC 0.93 0.73 1.98 A, B, C 0.83 3.90* 0.09

AC

* /7