Olanzapine, risperidone, and aripiprazole use in children and adolescents with Autism Spectrum Disorders

•Olanzapine is effective in treating the irritability associated with ASD.•Common side effects are sedation, increased duration of sleep, and weight gain with three antipsychotics.•Unfortunately, these side effects are more frequent with olanzapine than with the other antipsychotics. The aim of this study is to examine the use of olanzapine, risperidone and aripiprazole in autism spectrum disorders (ASD) in terms of their effects and side effects. ASD patients that had been initiated to be treated with one of the three antipsychotics that continued for a minimum of eight weeks were included in the study, retrospectively. The participants were recruited with 20 olanzapine using patients (2.5−10 mg/day) in comparison with 42 risperidone (1−4 mg/day) and 40 aripiprazole (3−15 mg/day) using patients that are using the matched equivalent chlorpromazine doses of the antipsychotics between the same time period. All three antipsychotics significantly decreased all of the ABC subscales scores in eight weeks. Sleepiness/sedation, increased duration of sleep, and weight gain were the most common side effects of the three antipsychotics and they were more frequent with olanzapine than with the others (X2 = 26.9, p < 0.0001; X2 = 20.8, p < 0.0001; X2 = 8.4, p = 0.01, respectively). Our results reveal that risperidone, aripiprazole, and olanzapine are effective in treatment of irritability, hyperactivity, social withdrawal, stereotypy, and inappropriate speech in ASD. But the side effects are more frequent with olanzapine and it should be considered when choosing antipsychotics for ASD.