Of 101 patients suffering from primary unipolar depression who were followed up for at least 1 year after recovery from the index episode, 51 relapsed into a new depressive episode within the year of recovery. Only those variables related to the period immediately after discharge distinguished nonrelapsers from relapsers; relapsers showed higher levels of residual symptoms, inferior social adaptation, a more pathological mean personality profile, and lower tricyclic plasma levels, despite similar dosage. The data are consistent with the hypothesis of an incomplete recovery from the index episode as a risk factor for relapse within 1 year.