Antipsychotic medicines are the mainstay of treatment of patients with psychosis. They are also used in the acute and long-term treatment of patients with bipolar disorder, depression and some other conditions. They have traditionally been divided into first-generation (‘typical’) and second-generation (‘atypical’) antipsychotics based on their ability to cause extrapyramidal symptoms. Metabolic adverse effects occur mainly with second-generation antipsychotics. They control the symptoms of psychosis with small differences in their efficacy, with the exception of clozapine, which is unique in its improved efficacy in treatment-resistant schizophrenia.