atypical antipsychotic

n. Newer drugs used to treat schizophrenia, delusional disorder, mania, deliria, and other extreme thought disorders and behavioral bizarreness or agitation are called atypical antipsychotics; they include clozapine, which has negative effects on the immune system, and more recently olanzapine, risperidone, quetapine, ziprasidone, and aripiprazole. These contrast with the older or typical antipsychotics developed in the middle of the 20th century called typical antipsychotics, such as the phenothiazines, butyrophenones, and thioxanthenes, which had more extreme side effects including extrapyramidal reactions.