Agomelatine augmentation of sertraline in the treatment of moderate to severe obsessive-compulsive disorder: a randomized double-blinded placebo-controlled clinical trial

BACKGROUND: As 40–60% of the patients with obsessive-compulsive disorder (OCD) do not adequately respond to the first-line treatment, finding an effective second-line treatment is required. Our aim was to assess the efficacy and safety of agomelatine (a selective melatonin receptor agonist and a 5-hydroxytryptamine (HT)2 C antagonist) augmentation of sertraline in the treatment of patients with moderate to severe OCD. METHODS: In this 12-week randomized, double-blinded, placebo-controlled, parallel-group clinical trial, 65 patients with moderate to severe OCD according to the Diagnostic and Statistical Manual of Mental Disorders-Fifth edition (DSM–5) criteria and a Yale-Brown obsessive compulsive scale (Y-BOCS) score of over 21, were included. They were assigned with sertraline (100 mg/day for the first 4 weeks and 200 mg/day for the next 8 weeks) and either agomelatine (25 mg/day) or placebo. The primary outcome was OCD symptoms measured by the Y-BOCS. RESULTS: Fifty patients (24 in agomelatine group and 26 in placebo group) completed the trial. The Y-BOCS scores in total (MD (95% CI) = 12.25 (11.00, 13.49) (P < 0.001) vs. MD (95% CI) = 12.46 (6.65, 15.74) (P < 0.001)), the obsession subscale (MD (95% CI) = 5.04 (4.19, 5.88) (P < 0.001) vs. MD (95% CI) = 5.00 (3.84, 6.16) (P = 0.0001)), and compulsion subscale (MD (95% CI) = 7.21 (6.34, 8.07) (P < 0.001) vs. MD (95% CI) = 7.460 (6.50, 8.42) (P < 0.001)) significantly decreased in both groups. Although, at the end of the trial, no significant difference was observed between the scores of the two groups in total (MD (95% CI) = 0.480 (-1.23, 2.19) (P = 0.78)), the obsession subscale (MD (95% CI) = 1.020 (-0.15, 2.19) (P = 0.38)), and the compulsion subscale (MD (95% CI) = 0.540 (-0.34, 1.42) (P = 0.54)). No major adverse effects were recorded, and the frequency of side effects was not significantly different between the groups. CONCLUSION: Agomelatine in augmentation with sertraline is safe and tolerable in patients with moderate to severe OCD. However, our study does not support its efficacy in improving OCD symptoms, compared to placebo. TRIAL REGISTRATION: The trial was registered at the Iranian Registry of Clinical Trials on 14/07/2020 (www.irct.ir; IRCT ID: IRCT20170123032145N5).