Update on typical and atypical antipsychotic drugs.

Antipsychotic drugs (APDs) are best classified as typical or atypical. The distinction is based solely on their ability to cause extrapyramidal side effects (EPS), including tardive dyskinesia (TD). The two classes differ in mechanism of action, with atypical APDs providing important modulation of serotonergic neurotransmission. TD increases the death rate and can be minimized by limiting use of typical APDs. Clozapine is unique among the atypical APDs in its efficacy for ameliorating psychosis in patients with treatment-resistant schizophrenia (TRS), for reduction of suicide, and for improving longevity. The typical and atypical APDs do not differ in improving psychopathology in non-TRS. The atypicals vary in metabolic side effects: some have little burden. Cognitive benefits of the atypical APDs may be superior for some domains of cognition and require less use of anticholinergic drugs, which impair memory, for treatment of EPS. Overall, choosing among the atypical APDs as first-line treatment represents the best course for schizophrenia and most likely other disorders for which APDs are used.