84% of autism patients reported improvement after six months of CBD-rich cannabis treatment

What the researchers found

After six months of treatment with cannabis oil (30% CBD, 1.5% THC), 82.4% of 188 ASD patients were still in active treatment. Of 93 patients assessed: 30.1% reported significant improvement, 53.7% moderate improvement, 6.4% slight improvement, and only 8.6% had no change. The most common side effect was restlessness (6.6%). No patients reported worsening.

Why it matters

This is one of the largest prospective studies of medical cannabis for autism, with 6-month follow-up data. The high continuation rate (82.4%) and broad improvement (83.8% of assessed patients) suggest the treatment is both tolerable and perceived as beneficial.

The numbers in context

188 ASD patients. 82.4% (155) still in active treatment at 6 months. 93 patients assessed: significant improvement 30.1%, moderate 53.7%, slight 6.4%, no change 8.6%. Side effects in 25.2%: restlessness 6.6% most common. Cannabis oil: 30% CBD, 1.5% THC.

How the study worked

Prospective observational study analyzing data collected as part of a treatment program for 188 ASD patients receiving medical cannabis between 2015-2017 in Israel. Treatment primarily used cannabis oil with 30% CBD and 1.5% THC. Outcomes assessed via structured questionnaires at 6 months.

What this study cannot tell us

No control group or blinding. Caregiver-reported outcomes are subjective. The 17.6% who discontinued and the additional patients not assessed at 6 months may have had different outcomes. Selection bias: patients who seek cannabis treatment may be predisposed to report benefit.

How to read the evidence

Rated moderate because this is a relatively large prospective study with structured data collection, though the lack of a control group limits causal inference.

When this study was published

Published in 2019. Co-authored by Raphael Mechoulam, who first synthesized THC. Additional controlled trials of cannabis for ASD have been initiated since.

The bigger picture

The autism-cannabis evidence base is growing rapidly, driven by strong parental demand and anecdotal reports. This study, from the group of Raphael Mechoulam (who first isolated THC), adds structured prospective data to what was previously almost entirely anecdotal evidence.

Questions still open

• Will randomized controlled trials confirm these results? Which specific ASD symptoms respond best to CBD-rich cannabis? What is the optimal CBD:THC ratio and dosing schedule for this population?

Common questions

Read the original research

Real life Experience of Medical Cannabis Treatment in Autism: Analysis of Safety and Efficacy.

Scientific reports, 9(1), 200

Citation

Bar-Lev Schleider, Lihi; Mechoulam, Raphael; Saban, Naama; Meiri, Gal; Novack, Victor. (2019). Real life Experience of Medical Cannabis Treatment in Autism: Analysis of Safety and Efficacy.. Scientific reports, 9(1), 200. https://doi.org/10.1038/s41598-018-37570-y

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