Cannabidiol (CBD), a non-intoxicating compound derived from the cannabis plant, has garnered increasing attention as a potential pharmacological therapeutic for autistic children. We conducted a randomised double-blind, placebo-controlled, crossover trial to understand whether oral CBD oil can improve behaviours in this population, with a primary focus on social relating outcomes, along with anxiety and parental stress. A total of 29 children (18 male), aged 5 to 12 years (M = 9.62 years, SD = 2.05), diagnosed with autism spectrum disorder, completed the study. Participants received weight-based dosing of CBD oil (10 mg/kg/day) or placebo oil over two 12-week intervention periods (crossover), separated by an 8-week washout period. Outcome measures included the Social Responsiveness Scale-2 (SRS-2; primary outcome), PROMIS Social Relating, Anxiety, and Sleep, Developmental Behaviour Checklist-2 (DBC-2), Vineland 3, and Autism Parenting Stress Index (APSI; secondary outcomes). There was no significant effect observed for the primary outcome measure (SRS-2) for CBD oil relative to placebo oil after 12 weeks, (p=.125). Significant improvements were observed in secondary measures of social functioning (PROMIS-Social, DBC-2 Social Relating; p<.05) and anxiety symptoms (PROMIS Anxiety, DBC-2 Anxiety; p<.05), while there was also a reduction in parental stress (p<.05). Safety and tolerability data indicated that two children experienced gastrointestinal discomfort while taking CBD. This pilot trial represents preliminary evidence for the potential therapeutic effects of CBD in autism. While further research is needed to confirm and extend these findings, the results suggest that CBD may be a promising intervention for addressing one of autism’s core symptoms: social relating. Future studies with larger sample sizes are needed to fully evaluate the efficacy and safety of CBD for autistic children.

The authors have declared no competing interest.

ACTRN12622000437763

This study did not receive any funding

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This trial received ethics approval from the Deakin University Human Research Ethics Committee (DUHREC 2020-071). Written informed consent was obtained from the parents/guardians of all participants prior to participation in the study, and assent was obtained from participants when appropriate.

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All data produced in the present study are available upon reasonable request to the authors