A retrospective cohort design using medical and pharmacy claims from one state's Medicaid program compared incidence rates for neurological adverse events associated with antipsychotic use in 4140 youths prescribed antipsychotic medications and an untreated sample of 4500 youths, January 1998 to December 2005. The treated cohort evinced a higher prevalence of involuntary movements, sedation, and seizures. The odds of incident involuntary, movements were significantly higher for those taking aripiprazole, risperidone, haloperidol, and multiple anti psychotics. The odds of incident seizures were greater for those taking risperidone, multiple antipsychotics, and serotonin-specific reuptake inhibitors. The odds of incident sedation were greater for those taking ziprasidone, risperidone, quetiapine, multiple antipsychotics, and serotonin-specific reuptake inhibitors. Exposure to risperidone, Multiple antipsychotics, and serotonin-specific reuptake inhibitors consistently confers a higher risk of developing a range of neurological adverse events in young patients, especially those with preexisting central nervous system, mental retardation, or cardiovascular disorders.