Clozapine is an antipsychotic that primarily has a blocking effect on 5-hydroxytryptamine receptors and dopamine receptors in the brain. It also has some effects on choline, histamine, and epinephrine, and can antagonize some of the effects of choline, histamine, and epinephrine. This drug rarely causes extrapyramidal reactions, generally does not cause an increase in blood prolactin, directly inhibits the brainstem reticular upstream activation system, and has a relatively powerful sedative and hypnotic effect. Clozapine is used clinically primarily as an antipsychotic, effective not only for positive symptoms of psychosis, but also for negative symptoms. It is indicated for all subtypes of acute and chronic schizophrenia, and is more effective for the hallucinatory-delusional and adolescent types. It can also reduce the affective symptoms associated with schizophrenia, such as depression, guilt and anxiety. It can also be used to treat mania, or other psychotic disorders with excitability and hallucinatory delusions, in addition to patients for whom traditional antipsychotic treatment has failed or is ineffective. Since this drug tends to cause granulocytopenia, it is generally not used as the drug of choice. In conclusion, clozapine is an antipsychotic.