New research, presented for the first time today at the International Psychogeriatrics Association (IPA) Meeting in Buenos Aires, Argentina, found that synthetic THC (dronabinol) was effective in reducing agitation in people with Alzheimer's dementia. The positive impact of the drug also led to improved mental health in caregivers of these patients. Brent Forester, MD, Psychiatrist-in-Chief and Chairman of the Department of Psychiatry at Tufts Medical Center and Director of Behavioral Health for Tufts Medicine, and Paul Rosenberg, MD, Co-Director of the Memory and Alzheimer's Treatment Center at Johns Hopkins Medicine, served as Co-Principal Investigators on the study.
There are currently seven million Americans living with Alzheimer's disease or types of dementia. Ninety percent of these people will develop behavioral issues as a symptom of their disease, with agitation--the most common of these syndromes--developing in 40 percent of individuals with dementia. Agitation, which can include both physical (pacing, wandering, inability to sit still) and verbal (yelling, screaming, verbal abuse) symptoms, also often adversely impacts the quality of life and mental health of families and caregivers; previous research has indicated links to increased risk of distress, physical and mental exhaustion, burnout and clinical depression. However, current therapies for agitation have demonstrated modest efficacy, and many have substantial safety concerns; commonly-used off-label antipsychotic medications carry an increased risk of stroke or death.
The THC-AD study included 75 outpatients with Alzheimer's type dementia, who were randomized to receive either 5 mg of dronabinol twice daily, or placebo, for a period of three weeks. Outcome data was collected from both patients and their caregivers. Results showed a statistically significant improvement in agitation in the dronabinol treated group, as measured by the total Pittsburgh Agitation Scale (PAS) and the Neuropsychiatric Inventory Agitation/Aggression subscale (NPI-C). In addition, the drug was well-tolerated, with safety data demonstrating minimal adverse effects and no drug interactions.
"THC-AD adds to the existing data supporting the safety and efficacy of synthetic THC to treat agitation, secondary to Alzheimer's type dementia," said Dr. Forester, who also serves as a professor and endowed Chair of Psychiatry at Tufts University School of Medicine. "Dronabinol appears to perform just as well, if not better, than the only other FDA-approved drug for agitation in this patient population currently on the market."
Dronabinol, a drug previously FDA-approved for nausea and vomiting in chemotherapy patients and for weight loss in patients with HIV and AIDS, impacts a cannabinoid receptor in the brain and affects mood, appetite and nausea. Previous data from a pilot study, and understanding of the drug's mechanism of action, suggested to the investigators that cannabinoid therapies may offer a therapeutic alternative to treating agitation in individuals with Alzheimer's type dementia.
"These new findings represent eight years of work dedicated to both Alzheimer's patients as well as their caregivers," said Dr. Rosenberg, a professor of Psychiatry and Behavioral Sciences at the Johns Hopkins University School of Medicine. "Agitation is one of the most distressing symptoms of Alzheimer's dementia, and we are pleased to make positive strides forward in treatment of these patients."
"It is the agitation, not the memory loss, that often drives individuals with dementia to the emergency department and long-term care facilities. Dronabinol has the potential to both reduce health care costs and make an important, positive impact on caregivers' mental and physical health," said Dr. Forester. "While further analyses are needed to better understand predictors of treatment response to help inform subsequent trials and clinical practice, the early results are quite encouraging."
Study sites included Johns Hopkins Medicine, Miami Jewish Health, McLean Hospital and Tufts Medical Center. The study was funded by a grant (R01AG050515) from the National Institute of Aging (NIA) part of the National Institutes of Health (NIH).
This content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health's National Institute on Aging.
Clinical Trial Number: NCT02792257
