A review of 834 cannabis clinical trials found registrations tripled from 30 in 2013 to 103 in 2021, with chronic pain, mental health, and neurological conditions as the most studied areas.
Medical cannabis researchers, pharmaceutical companies, policymakers, clinicians
834 trials; 30 in 2013 to 103 in 2021
What the researchers found
Of 2,966 reviewed trials, 834 met criteria. Annual registrations grew from 30 (2013) to 103 (2021). Over 40% of 2021 registrations were Phase II/III trials. THC and CBD dominated, with oral administration most common. Two-thirds of trials covered five therapeutic areas: chronic pain, mental/behavioral disorders, neurological diseases, metabolic diseases, and cancer. Pharmaceutical companies sponsored 39% of trials.
Why it matters
This provides the most comprehensive overview of the cannabis clinical trial landscape, revealing where research is concentrated and where significant gaps remain.
The numbers in context
834 of 2,966 trials included; 30 in 2013 to 103 in 2021; 40%+ were Phase II/III in 2021; mean enrollment: 128 (completed), 156 (ongoing), 542 (terminated); 39% pharma-sponsored
How the study worked
Review of four clinical trial registries (ICTRP, ClinicalTrials.gov, EUCTR, ANZCTR) for all interventional cannabinoid trials with therapeutic or drug development purposes registered between January 2000 and December 2021.
What this study cannot tell us
Registry data may not capture all trials. Registration does not guarantee completion or publication. Study quality cannot be assessed from registry data alone.
How to read the evidence
Comprehensive review of four major trial registries spanning 21 years provides a strong overview of the research landscape.
When this study was published
Published in 2022
The bigger picture
The rapid growth in cannabis clinical trials reflects both expanding legalization and increasing recognition that rigorous evidence is needed. The diversification into mental health, skin conditions, and new delivery methods signals a maturing field.
Questions still open
- Why do terminated trials have much larger mean enrollment (542) than completed ones (128)? Which therapeutic areas have the strongest completed trial evidence versus the most activity?
Common questions
How many clinical trials have been done on cannabis?
What conditions are most studied in cannabis trials?
Read the original research
The Characteristics of Clinical Trials on Cannabis and Cannabinoids: A Review of Trials for Therapeutic or Drug Development Purposes.
Pharmaceutical medicine, 36(6), 387-400
Citation
Modaresi, Farhang; Talachian, Kaivan. (2022). The Characteristics of Clinical Trials on Cannabis and Cannabinoids: A Review of Trials for Therapeutic or Drug Development Purposes.. Pharmaceutical medicine, 36(6), 387-400. https://doi.org/10.1007/s40290-022-00447-7
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