In a first-of-its-kind clinical trial, researchers have found that people with agitation and dementia in late life who took a special medical formulation of two active ingredients found in marijuana—THC and CBD—had significantly less agitation compared to those who received a placebo. The primary findings of the study were presented July 14, 2026, at the Alzheimer’s Association International Conference in London by Jacobo Mintzer, MD, of the Medical University of South Carolina and Georgetown University’s Brigid Reynolds, MSN, APRN, ANP-BC.
The LiBBY Trial Reports 90 Percent Patient Improvement
The study, dubbed the LiBBY trial (Life’s end Benefits of cannaBidiol and tetrahYdrocannabinol), enrolled 120 participants with Alzheimer’s disease or other types of dementia who were hospice-eligible and experiencing agitation. Ten medical centers nationwide conducted the LiBBY study visits at participants’ homes or places of residence. According to the researchers, close to 90% of study participants who received the treatment showed overall improvement after 12 weeks.
“These trial results were extremely impressive and showed a level of response not seen before in clinical trials related to dementia. Rarely do we see close to 90% of patients in a trial respond positively to a new medication,” said Mintzer, the co-lead investigator. Mintzer, who is also a psychiatrist at the Ralph H. Johnson VA Healthcare System, told Being Patient that the team made a commitment to find a treatment that could alleviate the symptoms and “take away the agitation and the despair of these patients.”
Agitation affects as many as half of the people who develop Alzheimer’s, manifesting as pacing, emotional distress, or verbal and physical aggression. “Agitation affects many people with late-stage dementia, causing symptoms such as restlessness, aggression, and emotional distress that can profoundly impact patients and their caregivers,” explained Reynolds, the co-lead investigator. “Current treatment options are limited and often carry significant side effects, underscoring the need for safer, more effective therapies.”
Existing medications such as morphine, Valium, and Haldol have had limited effectiveness in treating dementia-related agitation and can cause undesirable side effects. Furthermore, while there are two approved medications for treating Alzheimer’s agitation, their effects are small, may not be clinically meaningful, and have not been tested for those in the very late stages of the disease.
Researchers Administer Oral THC and CBD Formula
The LiBBY trial was designed to evaluate the effectiveness, safety, and tolerability of a combination of purified tetrahydrocannabinol (THC) and cannabidiol (CBD) given orally. The researchers created a novel formula comprising two mg of THC and 100 mg of CBD dissolved in digestible oil, administered twice daily. Compared to those who received the placebo, the THC/CBD treatment led to rapid improvement in symptoms at two weeks, which were sustained at 12 weeks.
External experts have noted the potential significance of these findings. “I think the findings are really intriguing,” Dr. Jerry Gurwitz, a geriatrician at UMass Chan Medical School, who was not involved in the study, told Being Patient. However, researchers have cautioned that this is an ongoing area of investigation and have not yet announced a Phase 3 trial.
The broader context of cannabis research remains complex. In the U.S., 30 states have legalized marijuana for medical use, but there is limited research on the drug’s effect on dementia patients because it is difficult to get trials approved, according to Dr. Nathan Herrmann, the head of the division of geriatric psychiatry at Sunnybrook Health Sciences Centre in Canada. “Based on some preliminary studies in other populations, like younger individuals with schizophrenia and bipolar disorder, as well as animal studies, there is at least some reason to theorize these drugs would have a benefit,” said Herrmann. “Therefore, there is a crucial need to do more, and larger studies in patients with Alzheimer’s disease to determine their effects and side effects.”
Herrmann also warned that marijuana-based treatments will not likely improve cognition in dementia patients. “In fact, there is good reason to be concerned that cannabinoids could make cognitive function worse,” he noted. Meanwhile, in the U.K., a separate trial funded by Alzheimer’s Research U.K. and led by researchers at King’s College London is testing a different drug called Sativex, a peppermint-flavored mouth spray containing both THC and CBD, on 60 patients between the ages of 55 and 90 living in care homes.
Readers should note that the LiBBY trial utilized a specific, purified medical formulation. Patients and caregivers should consult with qualified medical professionals regarding any potential treatment options for dementia-related agitation, as the safety and efficacy of commercial cannabis products remain unproven for this population.
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