Early symptomatic improvement affects treatment outcome in a study of major depressive disorder

This post-hoc analysis highlights the potent effect that early symptomatic improvement immediately following randomization can have on treatment outcome, and is particularly relevant for antidepressant drugs with rapid onset of action. The findings compel further exploration of possible moderating and mediating factors, including the experimental condition itself that can influence early response, and the need to identify “bio-types” within the population of MDD subjects.