Cannabis for Autism: Systematic Review Finds Very Limited Evidence From Clinical Trials | Research

The takeaway

Across 11 randomized trials of cannabis derivatives for autism, only one found improvement in global symptoms from whole-plant extract, while evidence certainty ranged from very low to low for all assessed outcomes.

Parents of children with autism considering cannabis treatments; clinicians advising on cannabis for autism; autism researchers

Only 11 RCTs exist for cannabis in autism

What the researchers found

Of 1,264 references screened, only 11 RCTs met inclusion criteria, with just four having available results for children/adolescents with autism. Five different cannabis formulations were tested. One trial showed cannabis whole-plant extract may improve global assessment symptoms, but results for other outcomes remained uncertain. No study assessed quality of life.

Why it matters

Families of children with autism are increasingly turning to cannabis products, often without clinical guidance. This review reveals that the evidence base is extremely thin -- only 11 RCTs exist, and the results are too uncertain to support confident clinical decisions.

The numbers in context

1,264 references screened; 11 RCTs included; 4 with results for children/adolescents; 5 cannabis formulations tested; evidence certainty very low to low

How the study worked

Systematic review following Cochrane Handbook methodology, reported per PRISMA 2020. Protocol registered with PROSPERO (CRD42023468300). Two independent reviewers assessed eligibility and extracted data. Searched 1,264 references.

What this study cannot tell us

Very few trials available. Different cannabis preparations, dosing, and outcome measures across studies made comparisons difficult. Most evidence rated very low to low certainty. No quality of life data available.

How to read the evidence

Cochrane-standard systematic review with PROSPERO registration, but the underlying evidence base is extremely limited with very low to low certainty ratings.

When this study was published

Published in 2025.

The bigger picture

The gap between public enthusiasm for cannabis as an autism treatment and the actual clinical evidence is stark. This review underscores that interest in cannabis for autism has far outpaced the research needed to know whether and how it helps.

Questions still open

Which specific cannabis formulation and dose, if any, might benefit specific autism symptoms? Why have so few RCTs been completed despite high public interest? What outcome measures should future trials prioritize?

Common questions

Should families use cannabis for autism based on this evidence?

The review found the evidence too uncertain to draw reliable conclusions. Only one trial showed potential benefit (whole-plant extract for global symptoms), and the certainty was rated very low to low.

Why is the evidence so limited?

Only 11 randomized trials exist, using five different cannabis formulations with different outcome measures. This makes it nearly impossible to draw firm conclusions. The field needs more and larger well-designed trials.

Read the original research

Therapeutic Use of Cannabis Derivatives and Their Analogs for Autism Spectrum Disorder: A Systematic Review.

Journal of clinical pharmacology, 65(11), 1339-1349

View on PubMed ↗Publisher’s paper ↗

Citation

Riera, Rachel; de Toledo, Isabela Porto; Farinasso, Cecília Menezes; Pacheco, Rafael Leite; Silva, Roberta Borges; Colpani, Verônica; Martimbianco, Ana Luiza Cabrera; Cruz, Camila Monteiro; Parreira, Patrícia do Carmo Silva; Latorraca, Carolina de Oliveira Cruz. (2025). Therapeutic Use of Cannabis Derivatives and Their Analogs for Autism Spectrum Disorder: A Systematic Review.. Journal of clinical pharmacology, 65(11), 1339-1349. https://doi.org/10.1002/jcph.70068