In the longest clinical trial of cannabinoids in Alzheimer's patients to date, a very low dose THC-CBD extract led to significantly higher cognitive scores compared to placebo over 26 weeks.
Alzheimer's patients and caregivers; medical cannabis researchers
26-week RCT: low-dose THC-CBD significantly improved cognitive scores vs placebo
What the researchers found
Patients receiving low-dose THC-CBD extract (0.350 mg THC + 0.245 mg CBD daily) had significantly higher Mini-Mental State Exam scores at week 26 compared to placebo.
Why it matters
Alzheimer's has very few effective treatments. A 26-week trial showing cognitive benefit with a remarkably low cannabinoid dose could open a new treatment avenue.
The numbers in context
Daily dose: 0.350 mg THC + 0.245 mg CBD. Duration: 26 weeks. Significant improvement in MMSE total score vs placebo.
How the study worked
Phase 2, randomized, double-blind, placebo-controlled trial. Participants aged 60-80 with Alzheimer's dementia received either placebo or THC-CBD extract orally for 26 weeks.
What this study cannot tell us
Phase 2 trial, likely small sample. Only the primary outcome was significant. Requires replication.
How to read the evidence
Randomized, double-blind, placebo-controlled Phase 2 trial; moderate because it needs replication.
When this study was published
2025 publication of a 26-week trial
The bigger picture
This is the first long-duration RCT to show a cognitive signal with cannabinoids in Alzheimer's.
Questions still open
- What is the mechanism at such a low dose? Can results be replicated in a larger Phase 3 trial?
Common questions
How low was the dose used?
Does this mean cannabis can treat Alzheimer's?
Read the original research
A randomized clinical trial of low-dose cannabis extract in Alzheimer's disease.
Journal of Alzheimer's disease : JAD, 108(4), 1602-1613
Citation
Cury, Rafael de Morais; da Silva, Taynara; Cezar-Dos-Santos, Fernando; Fakih, Yasmin Rafaela Correia; Narvaez, Karlin Andrea Ramírez; Gouvea, Murilo Chaves; Espínola, Carlos; Ferreira, Charles Francisco; de Castro, Wagner Antonio Chiba; Pamplona, Fabrício Alano; Silva, Elton Gomes da; Bicca, Maíra Assunção; Nascimento, Francisney Pinto. (2025). A randomized clinical trial of low-dose cannabis extract in Alzheimer's disease.. Journal of Alzheimer's disease : JAD, 108(4), 1602-1613. https://doi.org/10.1177/13872877251389608
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