Research Units on Pediatric Psychopharmacology (Rupp) Autism Network: Background and Rationale for an Initial Controlled Study of Risperidone

This article reviews the background and rationale for the choice of the atypical antipsychotic agent risperidone as the first drug to be studied by the RUPP Autism Network. Risperidone has potent effects on serotonin and dopamine neuronal systems, which have been implicated in the pathophysiology of autism. Unlike typical antipsychotics, such as haloperidol and pimozide, which have been shown to be effective for reducing many of the maladaptive behaviors associated with autism, the unique ratio of serotonin to dopamine receptor blockade for risperidone seems to produce a lower risk of acute and chronic extrapyramidial side effects and enhanced efficacy for the negative symptoms of autism. Indirect clinical and preclinical evidence supporting the use of risperidone to treat impaired social behaviour, interfering repetitive phenomena and aggressions as targets of pharmacotherapy for patients with autism are reviewed. The safety and tolerability of risperidone also are summarized.