Placebo-controlled study of relapse prevention with risperidone augmentation in older patients with resistant...

The effect of risperidone augmentation of citalopram for relapse prevention in older patients with antidepressant-resistant depression was evaluated.

Patients with major depression aged > or =55 years who had failed at least one adequate trial of an antidepressant received citalopram monotherapy (20-40 mg) for 4 to 6 weeks to confirm nonresponse (<50% reduction in Hamilton Rating Scale for Depression [HAM-D] scores). Those who achieved remission (HAM-D score < or =7 or Clinical Global Impressions severity score 1 or 2) after 4 to 6 weeks of open-label risperidone augmentation (0.25-1 mg) then entered a 24-week double-blind maintenance phase during which they received citalopram augmented with risperidone or placebo.

The patients' mean age was 63.4 +/- 7.9 years; 58% were women; 61% had received two or more antidepressants during the current episode; 93 met the criterion for citalopram nonresponse and entered open-label risperidone augmentation. Of the 89 patients who completed risperidone augmentation, 63 achieved symptom resolution and entered the 6-month double-blind maintenance phase: 32 received risperidone augmentation and 31 received placebo augmentation. The median time to relapse (Kaplan-Meier estimates) was 105 days in the risperidone group and 57 days in the placebo group (Wilcoxon chi(2): 3.2, df = 1, p = 0.069). Overall, 18 of 32 (56%) from the risperidone group and 20 of 31 (65%) from the placebo group relapsed. Treatment was well tolerated.

In older patients with resistant depression and poor response to standard treatments, risperidone augmentation resulted in symptom resolution in a substantial number of patients and a nonsignificant delay in time to relapse.