Assessing Rates and Predictors of Tachyphylaxis During the Prevention of Recurrent Episodes of Depression With Venlafaxine ER for Two Years (PREVENT) Study

Background: Antidepressant tachyphylaxis describes the return of apathetic depressive symptoms, such as fatigue and decreased motivation, despite continued use of a previously effective treatment. Methods: Data were collected from a multiphase, double-blind, placebo-controlled study that assessed the efficacy of venlafaxine extended release (ER) during 2 sequential 1-year maintenance phases (A and B) in patients with recurrent major depressive disorder (MDD). The primary outcome was the cumulative probability of tachyphylaxis in patients receiving venlafaxine ER, fluoxetine, or placebo. Tachyphylaxis was defined as Rothschild Scale for Antidepressant Tachyphylaxis (RSAT) score ≥ 7 in patients with prior satisfactory therapeutic response. A Kaplan–Meier