Schizophrenia is a major psychotic disorder. It is characterized by the presence of positive and negative symptoms such as delusions, hallucinations, disorganized speech, grossly disorganized and catatonic behaviors, and poor self-care. A person who is diagnosed as having schizophrenia must have psychotic disturbances that last for at least six months and include at least one month of active-phase symptoms (delusions, hallucinations, negative symptoms, etc.) (American Psychiatric Association, 2000). Schizophrenia is one of the most disabling mental illnesses and it affects a person's personality, perception, cognition, emotion, and behaviors. Consequently, it causes disturbances to a person's social, interpersonal, and vocational functioning. Five subtypes of schizophrenia exist: paranoid type, disorganized type, catatonic type, undifferentiated type, and residual type.