n. an atypical antipsychotic agent that is thought to exert its effects by acting both as a partial agonist of the dopamine D2 receptor and the serotonin 5-HT1A receptor and as an antagonist of the serotonin 5-HT2A receptor. It is used in the treatment of schizophrenia, bipolar I disorder, and irritability associated with autism and as an adjunct to SSRIs and SNRIs in treatment-resistant depression. U.S. trade name: Abilify.