Major depressive disorder, anhedonia and agomelatine: an open-label study.

Despite a wide range of available antidepressants, the effect of the treatment is often suboptimal and there is a need for more effective and better tolerated drugs. Unlike other antidepressants, agomelatine represents a new approach to depression with an innovative mechanism of action. It is an agonist of melatoninergic receptors MT1 and MT2 and a selective antagonist of 5-HT2c receptors. In this open-label 8-week study we aimed to investigate the efficacy of agomelatine on depressive symptoms in patients with major depression. Secondary endpoints were the effect of agomelatine on anhedonia. Thirty major depressive patients received a flexible dose (25-50 mg; per os, daily) of agomelatine. Depressive (Hamilton Depression Scale) and anxious (Hamilton Anxiety Scale) symptoms, anhedonia (Snaith Hamilton Rating Scale), and sleep quality (Leeds Sleep Evaluation Questionnaire) were assessed. Twenty-four patients (80%) completed 8 weeks of treatment. Significant improvements were seen at all visits on the HAM-D (p<.05), HAM-A(p<.01), SHAPS (p<.05), LSEQ (p<.05). Nine subjects (30%) were responders and 5 (17%) remitters at week 1; 18 (60%) were remitters by the end of the trial. There was no serious adverse event. No aminotrasferase elevations were noted. In line with previous studies, in which agomelatine was associated with early clinical improvement, this study also provides evidence of an early response and the findings of improvements in depression scores. Moreover, this is the first study where agomelatine was effective in the treatment of anhedonia. Additional trials are needed to delineate the place of agomelatine in the contemporary pharmacotherapy for depressive disorders.