THC-Based Medication Reduced Agitation in Alzheimer’s Patients in Randomized Clinical Trial

The research team, based at Johns Hopkins University School of Medicine and several collaborating centers, conducted the trial across five inpatient and outpatient research sites in the eastern United States. The study enrolled 75 adults diagnosed with Alzheimer’s-related agitation, using the International Psychogeriatric Association’s provisional criteria and requiring a minimum severity score on the Neuropsychiatric Inventory agitation and aggression domains. Participants were randomly assigned to receive either dronabinol or a placebo, with doses gradually increased to 10 mg per day, taken in two divided doses.

According to the researchers, 84% of participants completed the three-week study. Most were female, many were already taking psychotropic medications, and the group represented a diverse patient population. Despite severe cognitive impairment at baseline, individuals receiving dronabinol experienced a meaningful reduction in agitation.

On the Pittsburgh Agitation Scale, dronabinol produced a significantly greater week-to-week decline than placebo, with an effect size of 0.53. On the NPI-C agitation and aggression score, the decline favored dronabinol but did not reach statistical significance. Secondary outcomes—including sleep, daily functioning, overall agitation levels, cognition, intoxication, and the use of rescue medications such as lorazepam or trazodone—showed no between-group differences.

Researchers reported that dronabinol was generally well-tolerated. The only adverse event more common among those receiving THC was somnolence, and the study found no increase in intoxication or other safety concerns. The findings suggest that dronabinol may offer a safe therapeutic option for managing agitation in Alzheimer’s disease, a symptom that places heavy strain on both patients and caregivers and has limited treatment options today.