Mirtazapine treatment of Generalized Anxiety Disorder: a fixed dose, open label study

We investigated the efficacy of mirtazapine in the treatment of generalized anxiety disorder (GAD). Forty-four adult outpatients with GAD were treated openly with a fixed dose of mirtazapine (30 mg) for 12 weeks. The primary outcome measure was the change from baseline in total score on the Hamilton Rating Scale for Anxiety (HAM-A). The Clinical Global Impression of Improvement (CGI-I) was rated at the endpoint. Patients with a reduction of 50% or more on the HAM-A total score and a CGI-I score of 1 or 2 at endpoint were considered responders to treatment; remission was defined as a HAM-A score <= 7. At 12 weeks, response was achieved by 79.5% of the patients (n = 35) and remission by 36.4% of patients (n = 16). This study supports the notion that mirtazapine is an efficacious and well tolerated treatment for GAD. Limitations of the present study must be considered and further placebo-controlled trials are needed.