An Open-Label, Rater-Blinded, Augmentation Study of Aripiprazole in Treatment-Resistant Depression

Background: About 30% to 46% of patients with major depressive disorder (MDD) fail to fully respond to initial antidepressants. While treatment-resistant depression commonly refers to nonresponse or partial response to at least 2 adequate trials with antidepressants from different classes, due to variability in terminology, a staging system based on prior treatment response has been suggested. Aripiprazole is a novel atypical antipsychotic with partial agonism at dopamine D₂ and serotonin 5-HT_1A receptors and antagonism at the 5-HT₂ receptors. The present study evaluated whether augmentation with aripiprazole would be beneficial and tolerable in patients with treatment-resistant MDD who had failed 1 or more trials of antidepressants.

Method: In an open-label, rater-blinded study conducted from March 2003 through December 2003, 10 patients with DSM-IV MDD without psychotic features who had failed to respond to an adequate trial of at least 1 antidepressant were prescribed aripiprazole (10-30 mg/day) for 6 weeks. The dose of preexisting antidepressants remained unchanged. Treatment response was defined as a 50% or greater reduction in score on the Hamilton Rating Scale for Depression (HAM-D) from baseline to end of treatment. Secondary efficacy measures included scores on the Clinical Global Impressions-Improvement (CGI-I) and -Severity (CGI-S) scales.

Results: Eight of 10 patients had failed 2 or more antidepressant trials. The mean daily dose of aripiprazole was 13.21 mg. Intent-to-treat analysis showed that mean ± SD HAM-D scores reduced significantly from baseline (23.0 ± 8.1) to end of treatment (8.1 ± 6.0) (p < .001). There was a significant reduction in CGI-I (p < .05) and a trend toward decrease in CGI-S (p = .06) score. Seventy percent of the subjects were responders and 30% achieved remission. Common adverse effects were akathisia (20%), nausea (20%), andrestlessness (20%).

Conclusions: The study indicates the potential utility of aripiprazole as an augmenting agent in treatment-resistant depression, particularly in those who had failed 2 or more antidepressant trials. Adequately powered, randomized controlled trials are necessary to evaluate the role of aripiprazole in treatment-resistant depression.