Aim: The study aimed to identify social and psychological variables predictive of outcome in depression. A particular aim was to examine the additive effects of those variables, together with medication received subsequent to discharge, in relation to depressive relapse. The extent to which personality factors and the social support available to an individual conferred protection from, or increased vulnerability to, depressive relapse when that individual was subjected to adversity was also studied. Design and method: The study was procreative in design. Eighty patients, collected over a seven month period and screened for a new episode of unipolar depressive illness, were admitted to this study. The patients were re-interviewed following a substantial improvement in their condition. This second interview aimed to provide detailed information on aspects of the patients' marital relationships, the extent to which social support had been available, demographic and previous psychiatric history items and an assessment of personality. Those patients traced 28 weeks after inception into the study were given a third interview. This involved a reassessment of their symptomatic state and of a number of the measures included in the second interview. Additional information obtained in the third interview included an assessment of patients' use of health care resources and medication intake during the study periods. The final interview, the fourth, was designed to assess those social and environmental stresses to which patients had been subjected during the follow-up period. For most of the analysis, till patients were distinguished from swell patients on the basis of the severity of their symptoms at follow-up assessment. An index of support, based on the social resources available to study patients, was derived and a model developed and applied for estimating the adversity to which patients were subjected at a given time based on life stress information. Principal results: The severity of patients' symptoms at follow-up was related to the presence or absence of additional support prior to inception into the study and prior to follow-up. Relationships between stressful life events and outcome were clearly demonstrated only when time of event occurrence and the rated severity of events were considered. When both these factors were included in a dissipation model of adversity, a significant association was demonstrated between adversity suffered and follow-up symptom severity. Those patients having social support available who were subjected to adversity, suffered less severe symptoms at follow-up than patients similarly subjected to adversity but who did not have available social support. Availability of social support appeared to provide considerably more protection against a symptomatic response to adversity than did the taking of continuous medication. Obtaining a high extraversion score was associated with a significantly reduced risk of developing depressive symptoms in the presence of adversity (availability of support not considered). When the relative protective potency of available support and high extraversion was compared in patients subjected to adversity, support was found to confer greater immunity from symptoms than extraversion.