Schizophrenia: treatment targets beyond monoamine systems.

We develop the proposal in this review that schizophrenia is a syndrome made up of component symptom complexes, each with distinctive clinical correlates, pathophysiology, and selective treatments. Psychosis is the necessary component of the syndrome; it has a young-adult onset and is sensitive to current antipsychotic drugs. Cognitive dysfunction often precedes psychosis onset, does not present an episodic course, and is poorly responsive to antipsychotic drugs. Treatments for cognition are being developed largely on the basis of animal pharmacology. Drugs for component symptom complexes will theoretically be coadministered to independent symptomatic end points. Animal models, some with genetic characteristics, can be more easily and directly developed to match an individual component than to match an illness definition as broad as schizophrenia.