Risperidone-induced Somnambulism: A Case Report and Brief Review of Literature.

Atypical antipsychotic drugs have been recommended as the first-line agents in the treatment of schizophrenia. They are usually not associated with extrapyramidal symptoms and hyperprolactinemia. There is no previously reported case on somnambulism associated with risperidone intake. We report a case of risperidone-induced somnambulism in a schizophrenic patient. Somnambulism occurred while the patient was on a dose of 3 mg of risperidone per day. The dose was reduced to 2 mg per day along with the addition of clonazepam 0.5 mg daily at night. No further episode of somnambulism was reported after this. This case suggests the association of risperidone with occurrence of somnambulism. Further evidence to strengthen the causality of this needs to be gathered. This calls for prompt pharmacovigilance reporting of adverse drug events associated especially with antipsychotics.