Cannabinoids hold promise in the treatment of Alzheimer’s Disease.
For people living with Alzheimer’s and their caregivers, the newest research is welcome news.
Alzheimer’s Disease is the most common type of dementia and has no cure. 5 million Americans are living with this slow, progressive disease. It causes a loss of memories, impaired thinking and behavioral disturbances. 15 million Americans care for people with Alzheimer’s1.
To understand why the newest research is so promising, we must first walk through what we know about Alzheimer’s and Cannabinoids:
First, one of the major features of Alzheimer’s Disease includes abnormal plaques and tangles of protein in the brain. We’re not sure exactly how these proteins are involved, but we believe that they interfere with normal brain functioning and can cause nerve cell death1.
Second, inflammation plays an important role in Alzheimer’s. It is unclear if inflammation is the cause or the effect of Alzheimer’s. Regardless, the tangles and plaques that form are associated with worsening dementia and worsening inflammation2.
Third, CB1 receptors decline as Alzheimer’s progresses3.
Fourth, many Cannabinoids, such as Δ9-tetrahydrocannabinol (THC) and Endocannabinoids bind to CB1 receptors in the brain and have potent anti-inflammatory properties4, 5.
Finally, the newest evidence demonstrates that THC protects neurons in the brain by activating CB1 receptors. This reduces the toxicity of inflammation and stimulates the removal of amyloid plaques6.
Let’s pause for a recap: Alzheimer’s Disease causes neuronal plaques and tangles which are involved with inflammation that worsens the plaques and tangles. Also, CB1 receptors start to disappear during the course of the disease. Cannabinoids and Endocannabinoids bind to CB1 and have strong anti-inflammatory effects. The last piece of the puzzle is that THC has been demonstrated to reduce inflammation and reduce amyloid plaques in those with Alzheimer’s.
Can Medical Marijuana help people living with Alzheimer’s? Yes
As noted above, THC protects neurons in the brain by activating CB1 receptors. This reduces the toxicity of inflammation and stimulates the removal of amyloid plaques6.
Cannabidiol (CBD) and CBD-THC combinations have been studied less than THC as treatments in dementia. However, CBD has been noted to reduce inflammation, plaques, and tangles also9.
People with Alzheimer’s Disease tolerated cannabinoids well and demonstrate improved appetite, sleep, and agitated behaviors7.
One study found that a 4-week treatment with Medical Cannabis Oil twice-a-day was safe and well-tolerated. The treatment resulted in improved functioning and sleep quality. Patients demonstrated decreased delusions, agitation, aggression, irritability, and apathy. Also, Caregivers reported decreased burnout!8 Researchers gave patients 2.5 mg of Medical Cannabis Oil twice-a-day by mouth. They scheduled the dosing at 8am and 8pm. If there was no noticeable improvement or very little improvement, they increase both morning and evening doses by 2.5 mg two days later. The maximum dose in the study was 7.5mg twice-a-day. However, 64% of study participants only needed 2.5mg of oil twice-a-day. The oil had a 50:1 THC to CBD ratio.
At this time, there is a significant amount of evidence for safety, tolerability, and effectiveness of Cannabinoids in the treatment of Alzheimer’s disease.
Greig NH, Mattson MP, Perry T, et al: New therapeutic strategies and drug candidates for neurodegenerative diseases: p53 and TNF-alpha inhibitors, and GLP-1 receptor agonists. Ann N Y Acad Sci 1035:290-315, 2004
Farkas S, Nagy K, Palkovits M, et al: [¹²⁵I]SD7015 reveals fine modalities of CB₁ cannabinoid receptor density in the prefrontal cortex during progression of Alzheimer’s disease. Neurochem Int 60:286-91, 2012
Downer EJ and Finn DP: Cannabinoids: clearing the smoke on pain, inflammation and neurodegeneration. BR J Pharmacol 171:1341-44, 2014
Fagan SG and Campbell VA: The influence of cannabinoids on generic traits of neurodegeneration. BR J Pharmacol 171:1347-1360, 2014
Currais A, Quehenberger O, Armando AM, et al: Amyloid proteotoxicity initiates and inflammatory response blocked by cannabinoids. NPJ Aging Mech Dis 23, 2016
Antonsdottir IM, Makino KM, Porsteinsson AP: Dazed and Confused: Medical Cannabis in Alzheimer Disease. Am J Geriatric Psychiatry 24, 2016
Shelef A, Barak U, Berger U, et al: Safety and Efficacy of Medical Cannabis Oil for Behavioral and Psychological Symptoms of Dementia: An-Open Label, Add-On, Pilot Study. J Alzheimers Dis 51, 2016
Watt G, Karl T: In vivo Evidence for Therapeutic Properties of Cannabidiol (CBD) for Alzheimer’s Disease. Front Pharmacol 3:20, 2017
Dr. Zaraa is a board-certified psychiatrist in General Psychiatry and Child & Adolescent Psychiatry. He is an Assistant Professor Psychiatry at Case Western Reserve University School of Medicine and an Associate Professor at Baldwin Wallace University.