THC and CBD reduce agitation in patients with advanced dementia, clinical study shows
Clinical study points to symptom improvement in patients, while specialists reinforce the need for caution and more evidence.
A clinical trial presented during the Alzheimer’s Association International Conference 2026, in London, revealed that the combination of tetrahydrocannabinol (THC) and cannabidiol (CBD) can significantly reduce agitation in patients with late-stage dementia.
The study, named LiBBY trial (Life’s end Benefits of cannaBidiol and tetrahYdrocannabinol), included 120 participants with Alzheimer’s disease or other dementias, all eligible for palliative care and with relevant symptoms of agitation. The average age of the participants was 80 years.
Specific formulation showed consistent improvement
Patients received an oral formulation of purified THC and CBD in a fast-acting oil suspension, or a placebo. The study was conducted in a randomized, double-blind manner, meaning neither patients, caregivers, nor researchers knew who received the active treatment.
After two weeks, the treated group showed an average reduction of 6.27 points in agitation levels, measured by the Cohen-Mansfield Agitation Inventory scale. The effect was sustained and expanded over 12 weeks.
In addition, in the global clinical assessment of behavioral change, 83.9% of treated patients showed improvement after two weeks, compared to 30.5% in the placebo group. At 12 weeks, the figures were 87.2% versus 23.6%, respectively.
According to psychiatrist Jacobo Mintzer, co-author of the study, the observed response level is uncommon in dementia research. Meanwhile, researcher Brigid Reynolds highlighted the limitations of current therapies, which frequently cause significant side effects.
Treatment showed comparable safety profile
Adverse events, such as infections and gastrointestinal disorders, were similar between groups (46.7% in the treatment group versus 42.4% in the placebo group), and were considered expected for this patient profile.
In the extension phase of the study, between 13 and 24 weeks, all participants began receiving active treatment. Those who were already using the formulation maintained the benefits, while those who switched from placebo also experienced sustained reduction in agitation.
Caution with commercial products
Despite the promising results, researchers warn that the formulation used in the study is not equivalent to commercially available products.
“The medication was carefully developed, standardized, and administered under medical supervision. Products sold online or in dispensaries can vary significantly in composition and dosage,” Reynolds stated.
Clinical context and therapeutic need
Agitation is one of the most challenging symptoms in late-stage dementia, including manifestations such as restlessness, aggressiveness, and emotional distress, with a direct impact on the quality of life for patients and caregivers.
Currently, medications such as opioids, benzodiazepines, and antipsychotics are used, but they offer limited efficacy and significant risks, reinforcing the search for safer therapeutic alternatives.