Since serotonin 5-HT3 receptors are indirect inhibitors of dopamine release at the corticomesolimbic level, potentiation with the 5-HT3 receptor antagonist ondansetron in combination with SSRIs and antipsychotics has potential efficacy in patients with treatment-resistant obsessive-compulsive disorder [154]. The gene discussed is HTR3A; the disease is obsessive-compulsive disorder.