It has been reported that autism is a hypoglutamatergic disorder. Therefore, it was of interest to assess the efficacy of piracetam, a positive modulator of AMPA-sensitive glutamate receptors in autistic disorder. About 40 children between the ages three and 11 years (inclusive) with a DSM IV clinical diagnosis of autism and who were outpatients from a specialty clinic for children were recruited. The children presented with a chief complaint of severely disruptive symptoms related to autistic disorder. Patients were randomly allocated to piracetam + risperidone (Group A) or placebo + risperidone (Group B) for a 10-week, double-blind, placebo-controlled study. The dose of risperidone was titrated up to 2 mg/day for children between 10 and 40 kg and 3 mg/day for children weighting above 40 kg. The dose of piracetam was titrated up to 800 mg/day. Patients were assessed at baseline and after 2, 4, 6, 8 and 10 weeks of starting medication. The measure of the outcome was the Aberrant Behavior Checklist-Community (ABC-C) Rating Scale (total score). The ABC-C Rating Scale scores improved with piracetam. The difference between the two protocols was significant as indicated by the effect of group, the between subjects factor (F = 5.85, d.f. = 1, P = 0.02). The changes at the endpoint compared with baseline were: -11.90 [plus or minus] 3.79 (mean [plus or minus] SD) and -5.15 [plus or minus] 3.04 for group A and B respectively. A significant difference was observed on the change in scores in the ABC-C Rating Scale in week 10 compared with baseline in the two groups (t = 6.017, d.f. = 38, P [less than] 0.0001). The results suggest that a combination of atypical antipsychotic medications and a glutamate agent such as piracetam, might have increase synergistic effects in the treatment of autism.