Alzheimer’s disease (AD) is the leading cause of dementia and the 6th most common cause of death in the United States. Alzheimer’s disease is an irreversible, progressive neurodegenerative disorder that results in loss of memory and reasoning ability, and eventually a decline in physical capability. As the disease progresses, changes in personality are also common and can lead to significant depression and behavioral outbursts. All of these changes can be distressing both for patients suffering from AD and for families and caregivers, particularly as symptoms become more difficult to control. Tremendous research has been done to understand the mechanism of the disease and how we might best treat it, but unfortunately, there has been no cure and the treatments that are available do little if anything to slow the disease. I will briefly review the currently available and most commonly used therapies for patients with Alzheimer’s disease and discuss a potential role for cannabis.
Current Treatment for Alzheimer’s Disease
Right now, treatments for patients with Alzheimer’s disease are mostly supportive, as the available medical therapies have shown little benefit. Below is a summary of the current standard therapies:
- Cholinesterase inhibitors: the most common medications in this class of drugs are Aricept (donepezil), Exelon (rivastigmine), and Reminyl (galantamine). Patients with Alzheimer’s disease have decreased concentrations of acetylcholine in their brains, a neurotransmitter used to send signals from one part of the brain to the other. The theory behind these medications is that by preventing the breakdown of acetylcholine, more will be available and the brain will be able to function better. These medications do boost levels of acetylcholine, however, they have only shown mild benefit for enhancing memory, mood, and the ability to perform activities of daily living.
- Memantine: NMDA receptor activity is thought to play some harmful role in the disease process. Memantine, an NMDA receptor antagonist that blocks the function of the NMDA receptor, was therefore thought to be potentially useful. However, studies have shown the drug to only mildly decrease the disease’s progression.
- Antioxidants: free radical activity was, and to some extent is, thought to be involved in the pathologic development of brain disease. However, multiples studies examining the effect of antioxidants in Alzheimer’s disease have shown no benefit.
- Psychiatric therapy: behavioral and physical therapy, as well as psychiatric medications, may help patients and families handle symptoms such as depression, aggression, and sleep disturbances, but have no effect on the overall progression of the disease. Furthermore, the results of these therapies vary patient-to-patient. For some patients, psychiatric medications can sometimes lead to unpleasant side effects.
Overall, the available medical therapies do very little to influence disease progression and decrease symptoms. Strong social support may, in fact, be the most helpful to the patient and the family. Working with a network of social workers, aids, and other support staff can provide maximal independence for both the patient and the family, and can help to maintain safe environments. Clearly, though, there is tremendous room for improvement through the development of other medical therapies for patients with Alzheimer’s Disease.
Alzheimer’s Disease and Medical Cannabis
Several states now include “agitation of Alzheimer’s” as a qualifying condition for the use of medical cannabis. Amongst qualifying conditions, dementia is unique in that the patient may not have the capacity to decide whether to begin cannabis use. As such, it is up to the providers to be knowledgeable about potential benefits and harms and the caregivers to decide on use.
Understandably, providers and caretakers may be hesitant to treat dementia with cannabis. However, multiple recent studies have supported the safety and potential efficacy of cannabis for neurocognitive disorders. Of the more distressing symptoms for families of patients with Alzheimer’s Disease, agitation and sleep-wake disturbances (ex: sleeping all day and being awake all night) can impact the mental and physical health for everyone involved. In this respect, cannabis may prove useful, as there is data that suggests cannabis can decrease agitation and nighttime disturbances for patients. For a disease in which standard medical therapies have numerous potential side effects and can sometimes exacerbate delirium, cannabis-based therapy has the potential to provide a safe and palliative medication that would benefit not only the patient but family and caretakers as well.
Although more research needs to be completed to determine the best use of cannabis-based products for patients with Alzheimer’s Disease, research to date suggests a potential role for symptomatic relief. Given the multitude of available sedating medications, all of which have potential side effects, it is important for patients and families to discuss the risks and benefits of any medication with a doctor prior to starting such a therapy. For patients with refractory symptoms (symptoms that do not respond to standard therapy), or who prefer to avoid traditional sedating medications, cannabis may be an option.
Maust DT, Bonar EE, Ilgen MA, Blow FC, Kales HC. Agitation in Alzheimer’s Disease as a Qualifying Condition for Medical Marijuana in the U.S. The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry. 2016;24(11):1000-1003.
Shelef A 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. 2016;51(1):15-9.
Walther S et al. Delta-9-tetrahydrocannabinol for nighttime agitation in severe dementia. Psychopharmacology (Berl). 2006;185(4):524-8.
Woodward MR et al. Dronabinol for the treatment of agitation and aggressive behavior in acutely hospitalized severely demented patients with noncognitive behavioral symptoms. Am J Geriatr Psychiatry. 2014;22(4):415-9. doi: 10.1016/j.jagp.2012.11.022.
Van den Elsen GAH, Ahmed AIA, Verkes R-J, et al. Tetrahydrocannabinol for neuropsychiatric symptoms in dementia: A randomized controlled trial. Neurology. 2015;84(23):2338-2346.