Prophylactic effects or withdrawal reactions? An analysis of time-to-event data from antidepressant relapse prevention trials submitted to the FDA.

The placebo-antidepressant separation was disproportionally large between weeks 3 and 6 of the randomised maintenance phase. The benefits of continuing antidepressants relative to abrupt/rapid discontinuation declined sharply after week 6. This indicates an excess of relapse events in the placebo arms during the early maintenance phase that may be due to withdrawal reactions caused by abrupt/rapid discontinuation of active treatment. If these early relapse events are due to a direct pharmacological effect, then antidepressants' true prophylactic long-term effects are substantially overestimated.