Anxiety disorders are considered to be the most prevalent of the psychiatric disorders, with generalized anxiety disorder (GAD) being one of the most common in primary care practice. GAD is a chronic and disabling disorder, which is frequently underdiagnosed and undertreated. It is characterized by both psychic symptoms (particularly worry) and somatic symptoms, and often complicated by comorbid conditions such as depression.

Agomelatine, the first melatonergic antidepressant, has been shown to be effective and well tolerated, not only in treating major depressive disorder, but also in treating the anxiety symptoms of depression. These findings give impetus to investigation of its potential anxiolytic properties in GAD.

Two randomized, double-blind, placebo-controlled studies assessed the efficacy of agomelatine in GAD. The first, a 12-week study, used the HAM-A total score as the primary outcome measure. In the second, a relapse prevention study, the responders to a 16-week open treatment period with agomelatine were randomized to maintenance treatment with either agomelatine or placebo for a 26-week period.

In the short-term treatment of GAD,1 agomelatine was superior to placebo with a HAM-A total score difference of 3.28 (P = 0.04). In the maintenance treatment of GAD, the incidence of relapse was significantly lower with agomelatine than with placebo. Agomelatine was well tolerated in both trials.

In summary, these studies showed that the novel antidepressant agomelatine is also efficacious in the treatment of GAD.