Is there evidence for cannabis in autism spectrum disorder?

Cannabis for ASD has attracted significant research interest, particularly for managing behavioral symptoms (aggression, self-injury, anxiety, sleep disturbance) that are poorly addressed by existing medications. Biological rationale: ECS dysregulation has been proposed in ASD — animal models of autism show altered endocannabinoid signaling, and anandamide levels are reduced in some ASD patients. Clinical evidence: A 2019 Israeli observational study (Barchel et al., n=53) found CBD-rich cannabis oil significantly reduced behavioral problems, anxiety, and communication difficulties in children with ASD. A 2020 RCT (Aran et al., n=150) found CBD:THC (20:1) significantly reduced disruptive behavior vs. placebo. However: (1) Most studies use CBD-dominant preparations, not THC. (2) Sample sizes are small. (3) Behavioral outcome measures are subjective. (4) Long-term safety in children is unknown. (5) No studies have examined effects on core ASD features (social communication). Current evidence is promising but insufficient for clinical recommendations.