Switching from serotonin reuptake inhibitors to agomelatine in patients with refractory obsessive-compulsive disorder: a 3 month follow-up case series.

backgroundSerotonin reuptake inhibitors (SRIs) currently represent the cornerstone of obsessive-compulsive disorder (OCD) pharmacotherapy. However, OCD is characterized by high rates of partial and/or absent response to standard, recommended treatments, often prompting pharmacological and non-pharmacological augmentation or switching of strategies. Agomelatine, a novel melatonin agonist and selective serotonin antagonist (MASSA) antidepressant approved for major depressive disorder (MDD) has recently been additionally proposed as a treatment for anxiety disorders such as social anxiety disorder (SAD) and panic disorder (PD), but not yet OCD. Nonetheless, agomelatine may have a role in the management of OCD, essentially due to its anxiolytic 5-hydroxytryptamine (HT)2C blockade action, while melatonin (MT)1 and MT2 modulation might contribute to circadian rhythm restoration if impaired.

methodsThis case series reports the outcome of six patients with or without comorbid mood and/or other anxiety disorders who were treated with SRIs at adequate doses for at least 8 weeks, showing partial or no response. Patients were then switched to agomelatine 50 mg/day, and followed up for 12 weeks.

resultsThree out of six patients, in particular those with relevant circadian rhythm subjective impairment, showed a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score reduction of ≥35%. No relevant side effects were observed, but initial, transient, self-remitting dizziness in one patient and weight gain in another were seen.

conclusionsAlthough clinical confounding factors (subthreshold bipolarity and eventually the presence of impaired circadian rhythms) and methodological boundaries (lack of control and neurophysiological recording, tiny sample size and short follow-up) limit the validity of this preliminary observation, it does indicate agomelatine may have a role in some SRI-refractory OCD cases, thus prompting the validity of investigation by further controlled studies, even for drug-naïve OCD patients.