APA Dictionary of Psychology

n. any pharmacological agent used to control the symptoms of schizophrenia and other disorders characterized by impaired reality testing, as evidenced by severely disorganized thought, speech, and behavior. Formerly called major tranquilizers and later neuroleptics, antipsychotics are commonly divided into two major classes: conventional or typical (first-generation) antipsychotics, which were developed in the 1950s and include the phenothiazines and butyrophenones, and the newer atypical (novel or second-generation) antipsychotics, of which clozapine is the prototype, first marketed in the United States in 1990. The latter class has fewer adverse side effects than the former, particularly the neurologically based extrapyramidal symptoms but also the less serious yet unpleasant autonomic effects, such as dry mouth and blurred vision. However, the newer drugs have been associated with some serious metabolic and other effects (see atypical antipsychotic).