Use of agomelatine or N-[2-(7-methoxynaphthalen-1-yl)ethyl]acetamide or its hydrates, crystalline forms and acid/base additive salts, to obtain a drug for the treatment of generalized anxiety disorders. An independent claim is included for a composition comprising agomelatine, optionally in combination with excipients, for the manufacture of a drug to treat generalized anxiety disorders. ACTIVITY : Tranquilizer Antidepressant Hypnotic Cardiovascular-Gen Gastrointestinal-Gen Anorectic. MECHANISM OF ACTION : Melatoninergic system receptors agonist 5-HT2c receptor antagonist.