Extrapyramidal Syndromes and New Antipsychotic Drugs: Findings in Patients and Non-human Primate Models

Abstract

Since neuroleptic drugs were introduced in the 1950s they have become the primary mode of therapy for managing both acute and chronic psychoses. Although some antipsychotic drugs are free of disturbing extrapyramidal side-effects (EPS), most have a very narrow therapeutic/toxic index. Clozapine is the best example of an antipsychotic with a wide separation between antipsychotic actions and liability to EPS, but its side-effect profile of sedation, salivation, seizures, and agranulocytosis are factors that limit its use, and clearly indicate the need for further advancement in neuroleptic therapy.