Major depressive disorder. Initial results from a one-year prospective naturalistic follow-up study.

The authors present a 1-year prospective, naturalistic, longitudinal follow-up of 101 patients with the Research Diagnostic Criteria diagnosis of definite major depressive disorder. Seventy-four per cent of patients recover by 1 year. Of those who do recover, 36 per cent have subsequent Research Diagnostic Criteria affective episodes within the year. Episodes are of long duration for both the recovered and nonrecovered patients, being 30 weeks and at least 99 weeks, respectively. Certain commonly accepted ideas about the effects of age, sex, and marital status on the course and outcome of depression are not confirmed. It is demonstrated that factors which predict recovery and relapse must be differentiated. Duration of illness predict recovery but not future relapse, whereas number of previous episodes does not predict recovery but does predict future relapse.