Doctors make the diagnosis based on positive and negative symptoms. The prominent positive symptoms are: abnormal thinking, delusions and hallucinations. The negative symptoms are characterized by less interest, decreased emotional responsiveness, trying to be isolated and poor concentration on work. There are different types of this mental condition. Paranoid schizophrenia, hebephrenic schizophrenia, catatonic type, undifferentiated schizophrenia, residual and simple types. There may be post schizophrenic depression is seen in many patients after illness. When we talk about the treatments for schizophrenia, drugs alone cannot give a good prognosis. We should include talking treatments, community care, social and vocational training and medications in the treatment plan. Drugs using to treat schizophrenia are neuroleptics (antipsychotics) as risperidone amisulpride, olanzapine and paliperidone. There are no effective prevention methods since there is no reliable evidence of the development of this disorder. The only manageable preventive method is avoidance of drugs as cannabis, cocaine and etc.