Brief Psychiatric Rating Scale: A scale comprising 18 symptom constructs chosen to represent relatively independent dimensions of manifest psychopathology. The initial intended use was to provide more efficient assessment of treatment response in clinical psychopharmacology research; however, the scale was readily adapted to other uses. (From Hersen, M. and Bellack, A.S., Dictionary of Behavioral Assessment Techniques, p. 87)Schizophrenia: A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.Antipsychotic Agents: Agents that control agitated psychotic behavior, alleviate acute psychotic states, reduce psychotic symptoms, and exert a quieting effect. They are used in SCHIZOPHRENIA; senile dementia; transient psychosis following surgery; or MYOCARDIAL INFARCTION; etc. These drugs are often referred to as neuroleptics alluding to the tendency to produce neurological side effects, but not all antipsychotics are likely to produce such effects. Many of these drugs may also be effective against nausea, emesis, and pruritus.Schizophrenic Psychology: Study of mental processes and behavior of schizophrenics.Psychiatric Status Rating Scales: Standardized procedures utilizing rating scales or interview schedules carried out by health personnel for evaluating the degree of mental illness.Clozapine: A tricylic dibenzodiazepine, classified as an atypical antipsychotic agent. It binds several types of central nervous system receptors, and displays a unique pharmacological profile. Clozapine is a serotonin antagonist, with strong binding to 5-HT 2A/2C receptor subtype. It also displays strong affinity to several dopaminergic receptors, but shows only weak antagonism at the dopamine D2 receptor, a receptor commonly thought to modulate neuroleptic activity. Agranulocytosis is a major adverse effect associated with administration of this agent.Benzodiazepines: A group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring.Haloperidol: A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279)Risperidone: A selective blocker of DOPAMINE D2 RECEPTORS and SEROTONIN 5-HT2 RECEPTORS that acts as an atypical antipsychotic agent. It has been shown to improve both positive and negative symptoms in the treatment of SCHIZOPHRENIA.Psychotic Disorders: Disorders in which there is a loss of ego boundaries or a gross impairment in reality testing with delusions or prominent hallucinations. (From DSM-IV, 1994)Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Mental Disorders: Psychiatric illness or diseases manifested by breakdowns in the adaptational process expressed primarily as abnormalities of thought, feeling, and behavior producing either distress or impairment of function.Psychometrics: Assessment of psychological variables by the application of mathematical procedures.