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. No significant differences were detected between the placebo group and the cannabis group in terms of adverse events.

“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 stabilization in a half-year period.”

The study is the longest clinical trial ever conducted assessing cannabis’ effect on patients with AD-associated dementia.

Commenting on the study’s findings, NORML Deputy Director Paul Armentano said: “Because patients using cannabis exhibited changes in their cognitive scores but did not show similar improvements in secondary outcomes, such as sleep quality, it suggests that these cognitive improvements are a direct result of the cannabis intervention rather than an indirect result of other quality of life improvements.”

According to the findings of a review paper published last month in the Journal of Psychopharmacology, “Cannabinoids show promising potential in managing symptoms such as agitation and aggression in people with dementia, with an overall favorable safety and tolerability profile.”

Patient suffering from cancer, generalized anxiety disorder, and other conditions have similarly shown cognitive improvements following cannabinoid treatment.

Full text of the trial, “A randomized clinical trial of low-dose cannabis extracts in Alzheimer’s disease,” appears in the Journal of Alzheimer’s Disease. Additional information on cannabis and Alzheimer’s disease is available from NORML’s publication, Clinical Applications for Cannabis and Cannabinoids.