Patients suffering from dementia associated with Alzheimer’s disease (AD) exhibit cognitive improvements following the sustained use of plant-derived cannabinoid extracts, according to placebo-controlled clinical trial data published in the Journal of Alzheimer’s Disease.
An international team of investigators from Brazil and the United States compared the efficacy of low-dose cannabis extracts versus placebo in 28 patients with AD-associated dementia. Study participants consumed either a THC-CBD balanced extract or a placebo daily for 26 weeks. Patients’ cognitive performance was assessed at baseline and at 4, 8, 12 and 26 weeks.
Patients who received the placebo experienced an overall decrease in their cognitive performance while those receiving cannabis showed cognitive improvements. Researchers described cannabis’ efficacy as “superior” to those of traditional Alzheimer’s medications.
“In this trial, we report the administration of very low doses of cannabis extract to AD patients … significant[ly] alleviated cognitive loss over a 6-month follow-up period compared to the placebo group” the study’s authors concluded. “Considering AD progression accentuated cognitive decline, we achieved with cannabis treatment remarkable disease stabilisation in a half-year period”.
The study is the longest clinical trial ever conducted assessing cannabis’ effect on patients with AD-associated dementia.
2 November, 2025