Brief report: effects of clozapine on self-injurious behavior of two risperidone nonresponders with mental retardation.

Atypical antipsychotic medications for self-injurious behavior (SIB), aggression, and destruction among people with mental retardation and development disabilities are becoming increasingly accepted. Most studies are on risperidone and fewer have been conducted on clozapine. The present single-blind study reports marked reductions in SIB and aggression of two persons with profound mental retardation who were nonresponsive to all other behavioral and psychopharmacological interventions, including risperidone. The most effective dose was 200 mg/day. Side effects were mild and the drug was tolerated well.

The effect of clozapine on self-injurious behavior.

Traditional neuroleptic drugs like thioridazine and haloperidol have not proven to be systematically effective with the treatment of self-injurious behavior (SIB). These drugs may be ineffective because they primarily block D2 dopamine receptors. Based on research with humans and other animals, it appears that another dopamine receptor, D1, may be responsible for mediating some SIB. Clozapine, a neuroleptic recently introduced in the United States, has proven effective in treatment of refractory cases of schizophrenia and is known to have an affinity for blocking D1 receptors. The drug was used to complete a 93-week double-blind crossover trial with a client displaying chronic SIB. Though clozapine is known to affect other neurotransmitter systems, the successful treatment of the participant is consistent with the D1 hypothesis of self-injurious behavior and suggests the possibility that clozapine could be an effective pharmacological intervention for some cases of SIB.