Venlafaxine Versus Placebo in the Preventive Treatment of Recurrent Major Depression

Background: Major depression is often chronic and recurrent, yet most long-term therapeutic trials are not adequately designed to assess antidepressant efficacy in recurrence prevention. Long-term efficacy and safety of prophylactic venlafaxine treatment were evaluated in outpatients with recurrent major depression.

Method: Patients with a history of recurrent DSM-III-R major depression received open-label treatment with venlafaxine, 100 to 200 mg/day, for 6 months. Those who responded to treatment (Hamilton Rating Scale for Depression [HAM-D₂₁] score <= 12, day 56) and remained relapse-free (no more than 2 HAM-D₂₁ scores > 10 and no Clinical Global Impressions-Severity of Illness [CGI-S] score >= 4, months 2-6) either continued taking venlafaxine, 100 to 200 mg/day, or were switched in a double-blind fashion to placebo for 12 months. The primary efficacy outcome was the number of patients experiencing a recurrence of major depression (CGI-S score >= 4). The cumulative probability of recurrence was calculated using the Kaplan-Meier method of survival analysis. Data were collected from November 1992 through December 1995.

Results: Of the 235 patients who enrolled in the recurrence-prevention period, 225 (N = 109, venlafaxine; N = 116, placebo) provided efficacy data. Survival analysis determined a 22% cumulative probability of recurrence in venlafaxine-treated patients after 12 months compared with 55% for the placebo group (p < .001). More than twice as many placebo-treated patients (48%) as venlafaxine-treated patients (21%) discontinued treatment because of lack of efficacy (p < .001).

Conclusion: Twelve-month maintenance venlafaxine treatment was significantly more efficacious than placebo in preventing major depression recurrence in patients who had been successfully treated with venlafaxine for 6 months.