ANTIPSYCHOTICS

n. pharmacological agents used in the treatment of schizophrenia, mania, delirium, and other forms of thought disorder and uncontrolled behavioral agitation. Formerly and historically called major tranquilizers, these drugs are commonly divided into two major classes: conventional (typical or first-generation) antipsychotics and newer atypical antipsychotics - for which clozapine is an example. The newer atypical class has fewer adverse side effects, but may cause drastic weight gain. Antipsychotics exert their effects by various mechanisms, including antagonism of dopamine D2 receptors, which is important in disorders in which excess dopamine is the issue. See also atypical antipsychotics.