l-carnitine adjunct to risperidone for treatment of autism spectrum disorder-associated behaviors: a randomized, double-blind clinical trial

The present study was designed to evaluate the efficacy and safety of l-carnitine as an adjuvant agent to risperidone in the treatment of autism spectrum disorder (ASD)-associated behaviors. In this study, 68 children with confirmed ASD were randomly allocated to receive either l-carnitine (150 mg/day) or matched placebo in addition to risperidone. We utilized the Aberrant Behavior Checklist-Community Edition scale (ABC-C) and a checklist of potential adverse effects to assess changes in behavioral status and safety profile at weeks 0, 5 and 10 of the trial. The primary outcome was defined as a change in the irritability subscale score. Sixty patients with similar baseline characteristics completed the trial period. Although scores of ABC-C subscales significantly decreased in both groups over the trial period, the combination of l-carnitine and risperidone resulted in more reduction on the irritability and hyperactivity subscales compared to the combination of risperidone and placebo ( P = 0.033 and P < 0.001, respectively). However, changes in lethargy, stereotypic behavior and inappropriate speech subscales were similar between groups. In conclusion, l-carnitine adjuvant to risperidone could improve irritability and hyperactivity features in children with ASD. Results of this study should be considered preliminary and further clinical trials with larger sample sizes and longer follow-up periods are warranted.