The effect of intravenous, intranasal, and oral ketamine in mood disorders: A meta-analysis.

Background: Ketamine is established as a rapid and effective treatment in adults with treatment-resistant depression (TRD). The availability of different formulations and routes of delivery invites the need for evaluating relative effect sizes.

Methods: Effect size with respect to depression symptom reduction for each formulation and route of delivery was compared at discrete time-points (i.