MSH: A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.,CSP: class of psychoses with disturbance mainly of cognition (content and form of thought, perception, sense of self versus external world, volition) and psychomotor function, rather than affect.,MEDLINEPLUS: Schizophrenia is a severe, lifelong brain disorder. People who have it may hear voices, see things that aren't there or believe that others are reading or controlling their minds. In men, symptoms usually start in the late teens and early 20s. They include hallucinations, or seeing things, and delusions such as hearing voices. For women, they start in the mid-20s to early 30s. Other symptoms include Unusual thoughts or perceptions Disorders of movement Difficulty speaking and expressing emotion Problems with attention, memory and organization No one is sure what