It exerts therapeutic effects may by antagonizing 5-HT1A, 5-HT2A, D1, D2, and H1 receptors as well as α1/2- adrenergic receptors.436,437 Dexmedetomidine is an α2-adrenergic receptor agonist that can be used for the acute treatment of agitation associated with schizophrenia or bipolar I or II disorders.438 Risperidone, an atypical antipsychotic drug, is now used as maintenance therapy for patients with bipolar I disorder.439. This evidence concerns the gene HTR2A and schizophrenia.