Significance of neuroleptic dose and plasma level in the pharmacological treatment of psychoses.

The clinical use of antipsychotic agents may be enhanced by considering their dose-effect characteristics. In particular, assessment of immediate and later follow-up treatment of psychotic patients (1) indicates that moderate doses are adequate for most patients, (2) fails to support the utility of unusually high doses, and (3) even suggests the existence of a biphasic relationship of antipsychotic efficacy to dose of neuroleptics and possibly to plasma concentrations of the drugs as well. Trends toward lesser overall clinical benefits of high doses may reflect untoward extrapyramidal or other central nervous system effects leading to behavioral and cognitive symptoms. Thus, moderate doses of neuroleptics appear, on average, to be about as effective as, and probably safer than, the larger doses that have been popular in the United States in recent years.