Prior Antidepressant Treatment Trials May Predict a Greater Risk of Depressive Relapse During Antidepressant Maintenance Therapy

Abstract Background We examined the influence of prior antidepressant treatment trials on the likelihood of depressive relapse, and time to depressive relapse, during maintenance therapy of bipolar II disorder in treatment-responsive subjects who had recovered from a major depressive episode. Methods Data were derived from a prospective, randomized, double-blind trial of 148 adult subjects with bipolar II major depressive episode who were initially administered open-label fluoxetine monotherapy for 12 weeks. Remitters with a final Hamilton Rating Scale for Depression score of 8 or lower were then randomized to continuation therapy with either fluoxetine (n = 28), lithium (n = 26), or placebo (n = 27) for 50 additional weeks. Results An increase in the number of prior antidepressant treatment trials was significantly associated with a greater likelihood of depressive relapse for all treatment conditions taken together [odds ratio (OR) = 1.42, z = 2.49, P = 0.01] and for the 2 active treatment conditions together (OR = 1.51, z = 2.28, P = 0.02). An increase in the number of prior antidepressant trials was also associated with a trend-level shortening in the time to relapse for all treatment conditions taken together (hazard ratio = 1.15; confidence interval, 0.99–1.35; P = 0.07) and a significantly shorter time to relapse for subjects in the 2 active treatment conditions (hazard ratio = 1.30; confidence interval, 1.05–1.62; P = 0.02). Conclusions These findings support prior evidence of a negative influence of the number of prior antidepressant treatment trials on the likelihood of response and suggest that the number of prior antidepressant trials may also be associated with a greater odds of depressive relapse, and a shorter time to relapse, during antidepressant maintenance therapy in recovered depressed subjects with bipolar II disorder.