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.