Three-year outcomes for maintenance therapies in recurrent depression. We conducted a randomized 3-year maintenance trial in 128 patients with recurrent depression who had responded to combined short-term and continuation treatment with imipramine hydrochloride and interpersonal psychotherapy. A five-cell design was used to determine whether a maintenance form of interpersonal psychotherapy alone or in combination with medication could play a significant role in the prevention of recurrence. A second question was whether maintaining antidepressant medication at the dosage used to treat the acute episode rather than decreasing to a "maintenance" dosage would provide prophylaxis superior to that observed in earlier trials in which a maintenance dosage strategy was employed. Survival analysis demonstrated a highly significant prophylactic effect for active imipramine hydrochloride maintained at an average dose of 200 mg and a modest prophylactic effect for monthly interpersonal psychotherapy. We conclude that active imipramine hydrochloride maintained at an average dose of 200 mg is an effective means of preventing recurrence and that monthly interpersonal psychotherapy serves to lengthen the time between episodes in patients not receiving active medication. 