A comparison of life events in patients with unipolar disorder or bipolar disorder and controls.

OBJECTIVE: The present study aimed to explore the association between stressful life events (LEs) and the development of affective psychopathology.

METHOD: Thirty patients with unipolar disorder and 30 patients with bipolar disorder were compared to 60 matched healthy controls in regard to the rate of stressful LEs. Assessment measures included the Beck Depression Inventory, the Adult Life Events Questionnaire, and the Childhood Life Events List.

RESULTS: The entire sample of affective patients had more LEs in general, more negative LEs, and more loss-related LEs in the year preceding their first depressive episode as compared with normal controls. Subjects with unipolar disorder had more positive LEs and more achievement LEs, whereas subjects with bipolar disorder had more uncontrollable LEs in the year preceding the first depressive episode. The relationship between LEs and manic episodes was prominent in the year preceding the first manic episode, with subjects with bipolar disorder reporting more LEs in general and more ambiguous events in that year. Almost no significant differences on LE frequency were observed in the year before the last depressive and manic episodes in the patient groups with unipolar and bipolar disorder. A significant relationship was found between childhood LEs and the development of affective disorders in adulthood, with patients with unipolar disorder exhibiting less positive and achievement LEs.

CONCLUSIONS: In both the unipolar and the bipolar groups, the major impact of LEs on the onset of affective disorders was found in the year before the first depressive or manic episodes. This suggests that the accumulation of stressful LEs at this crucial period contributes to the precipitation of a pathological response mechanism. Once established, this mechanism would be reactivated in the future by even less numerous and less severe stressors, compatible with the kindling hypothesis.