Schizophrenia is a major psychiatric disorder characterized in the International Classification of Diseases as involving a syndrome of disorders of thought, perception, affect, and behavior (ICD F20- 29). So-called productive or positive symptoms include possibly more obvious manifestations, including delusions, hallucinations, and thought pattern disorders such as "knight's move thinking" or loosening of associations. These positive characteristics tend to be associated with the onset of schizophrenia as an illness and with acute relapses of the illness and are the aspects of the illness most likely to be modeled by drug-induced schizophrenia-like episodes. . On the other hand, other characteristics that are more difficult to treat include cognitive symptoms and so-called negative symptoms. These include low motivation, loss of will, weakening of affect, and poverty of thought, speech, and action. Schizophrenia is considered a rare disorder with a lifetime risk of 7.2 per 1,000. Although it is rare in terms of incidence (0.4%), as it tends to appear early in the adulthood and to last a lifetime., ...