The efficacy of venlafaxine prolonged-release capsules as a treatment for generalised anxiety disorder (GAD) was established in two 8-week, placebo-controlled, fixed-dose studies (75 to 225 mg/ day), one 6-month, placebo-controlled, fixed-dose study (75 to 225 mg/ day), and one 6-month, placebo-controlled, flexible-dose study (37.5, 75, and 150 mg/ day) in adult outpatients.