The development of major depressive episodes during the course of dysthymic and episodic major depressive disorders: a retrospective examination of life events.

BACKGROUND

The present study examined whether stressful life events are associated with the development of major depressive episodes (MDEs) in a longitudinal, retrospective study of dysthymic and episodic major depressive disorders.

METHODS

Sixty-seven outpatients with DSM-III-R dysthymia and 38 outpatients with non-chronic major depression were followed up 30-60 months after entry into the study. Follow-up assessments included a modified version of Paykel's (1997) Interview for Recent Life Events (IRLE) and Keller et al.'s (1987) Longitudinal Interval Follow-up Evaluation. Life events were assessed retrospectively in the 6 months before the most recent MDE or in the 6 months before follow-up for patients without a MDE.

RESULTS

In dysthymic patients, MDEs were significantly associated with a new life event in the context of an ongoing chronic stressor. In episodic major depressive patients, relapses were associated with new life events regardless of an ongoing chronic stressor.

LIMITATIONS: This was a retrospective study. It was also a conservative test of the association between life events and MDEs as the follow-up period over which life events were assessed was long, increasing the possibility of forgetting; events occurring less than 1 month before relapse were excluded to avoid confounding the event with the MDE; life events were assessed for a more distant time period for patients who experienced MDEs than those who did not; and an abbreviated version of the IRLE was used which may have failed to identify less severe events.

CONCLUSIONS

This study suggests that life events may play a role in the onset of MDEs in persons with dysthymic disorder and those with major depressive disorder. Thus, clinicians should monitor dysthymic patients after a stressful life event, particularly if it occurs in the context of a chronic, ongoing stressor.