Schizophrenia: One of several brain diseases whose symptoms that may include loss of personality (flat affect), agitation, catatonia, confusion, psychosis, unusual behavior, and withdrawal. The illness usually begins in early adulthood.

The causes of schizophrenia are not yet fully known. Schizophrenia is not caused by poor parenting practices. A variant version of a gene called COMT has been found to increase the risk for developing schizophrenia. The normal version of the COMT gene helps process dopamine, a brain chemical. The variant version of the COMT gene is less active in this regard. Other genes and environmental factors may well be involved in schizophrenia.

Treatment is with neuroleptic medication and supportive interpersonal therapy. The prognosis is currently fairly good, with two-thirds of those diagnosed recovering significantly.