How long should a trial of escitalopram treatment be in patients with major depressive disorder, generalised anxiety disorder or social anxiety disorder? An exploration of the randomised controlled trial database

Objective To extend the knowledge of course of improvement in patients with major depressive disorder (MDD), social anxiety disorder (SAD) or generalised anxiety disorder (GAD) participating in randomised placebo‐controlled trials (RCTs) and to infer the optimal duration of initial escitalopram treatment in clinical practice, after which intervention might be reasonable in case of non‐response. Methods Post hoc analysis of pooled clinical trial database for escitalopram in MDD (14 studies), GAD (4 studies) and SAD (2 studies). ‘Onset’ of action was defined as a 20% or more decrease from baseline score in disorder‐specific psychopathological rating scales: ‘response’ as a 50% or more decrease from baseline score. Results In MDD, the probability of responding at week 8 if no onset was apparent at week 2 was 43%; in patients with an onset of effect the probability was nearly 80%. Similar patterns were observed in GAD and SAD. The chance of responding beyond week 4 in MDD, GAD and SAD was 20% or less if no effect had occurred by week 2. Conclusions The pattern of response in these RCTs suggests that in patients with MDD, GAD or SAD in wider clinical practice, a period of at least 4 weeks is worthwhile before considering further intervention. Copyright © 2009 John Wiley & Sons, Ltd.