A placebo double-blind pilot study of dextromethorphan for problematic behaviors in children with autism.

We used a mixed group/single-case, double-blind, placebo-controlled, ABAB design to examine the safety and efficacy of the glutamate antagonist dextromethorphan for the treatment of problematic behaviors and core symptoms in eight children diagnosed with autism. All participants had increased levels of irritability at baseline as measured by the Aberrant Behavior Checklist, and demonstrated a wide variety of problematic behaviors. Group analyses revealed that dextromethorphan was equivalent to placebo in the treatment of problem behaviors and core symptoms. Analyses at the single-subject level demonstrated that three of the eight participants who had a behavioral profile consistent with attention-deficit hyperactivity disorder responded positively to dextromethorphan. Future research that employs a larger, more homogeneous sample is necessary to replicate the findings from this study.