The aim of the thesis was to examine the stressor-vulnerability-stressor model of depression. Specifically, according to Beck's (1983) theory, it was proposed
that specific personality styles of sociotropy and autonomy (underlying dysfunctional cognitive schemas) would moderate the effects of congruent matched life events. It was also proposed that negative automatic thoughts (surface distorted cognitions) would mediate the relation between the diathesis-stress interaction and depressive symptoms. A cross-sectional and longitudinal design was used to test 82 pre and 76 postpartum women. Women were assessed in the last trimester of pregnancy (Time 1) and again 2- months postpartum (Time 2) on measures of sociotropy and autonomy personality styles (Revised Personality Style Inventroy, PSI-II), and subjective perceptions of interpersonal and achievement loss associated with sociotropic and autonomous negative life events (adapted from Clark, et al., 1992). Subsidiary measures to assess marital satisfaction and infant temperament were included to investigate personality style as a moderator of perceived marital satisfaction and child
temperament in relation to depression in this population. The Automatic Thoughts Questionnaire was included to determine whether negative automatic thoughts would mediate the relationship between distal predictors and depressive symptoms measured by the Beck Depression Inventory (BDI) and the Edmburgh Postpartum Depression Scale (EPDS). In general, the results of the studies supported the moderating role of the cognitive diathesis and the mediating role of autonomic thoughts in the causal pathway to depression. However, results generally did not support the specific personality stressor-vulnerability model. High sociotropy personality style is associated with higher depression scores prenatally and increases in depression scores postpartum. Therefore, there is some support for it being a risk factor. Several instances showed increases in depression scores were associated with combinations of high sociotropy personality and high loss perceptions of life events both during pregnancy
and the transition/follow-up period, in both interpersonal and achievement domains. Direct effects were foimd for autonomy personality in association with higher depression scores in pregnancy but also evidence to support a general cognitive-diathesis effect in pregnancy and in predicting slight increases in depression postpartum. Again, specific type of loss varied and suggests a general diathesis model rather congniency model. No association was found with autonomy personality and transitional life events and depression postpartum. Most interestingly, women who showed the most positive adjustment to motherhood in terms of reduction in depression scores were those who were low sociotropy or low autonomy personality styles and who reported minimal achievement loss associated with life events during pregnancy and follow-up. No association was found between marital satisfaction during pregnancy or the transition period and depressive symptoms postpartum either directly or indirectly.
Maternal ratings of infant temperament, but not paternal ratings, were directly associated with depressive symptoms in the postpartum period. While the results are inconclusive, women with high autonomy personality may be more sensitive to the events occurring during pregnancy, while sociotropy personality appeared to be sensitive to the events occurring during pregnancy and particularly the follow-up period.
In conclusion, this research has indicated that a cognitive diathesis-stress model predicts depressive symptoms postpartum. However, a congruent match between cognitive-personality diathesis and perceived loss from life events may not need to exist to activate the vulnerability. Implications for both future research in the stressor-vulnerability area and subsequent approach to treatment is discussed within the framework of furthering the notion that the personality-life event "match" may be
better understood by exploring the certain types of adversity (stress) that may be generated by the personality type.