Alzheimer's disease is a devastating illness. People with Alzheimer's suffer from progressive memory loss, cognition impairment, physical deterioration and eventual death. Current treatment methods can slow disease progression, but they do not stop or prevent it.
Recent studies have shown that medical marijuana may help with Alzheimer's symptoms, slow progression and provide some prevention.
Alzheimer's and the Brain
Alzheimer's disease is the most common form of dementia in the United States. The Alzheimer's Association estimates that in 2015, 5.3 million Americans will have Alzheimer's. It is the sixth leading cause of death in total, and is responsible for 32% of deaths in adults 65 and older in the United States.
In Alzheimer's, protein plaques, called beta-amyloids, build up between the nerve cells, particularly those responsible for memory and cognition. The plaques disrupt cell communication leading to loss of function. Additionally, tau proteins form tangled fibers inside the brain cells, preventing nutrients from reaching the cells. Both abnormalities eventually cause cell death.
Alzheimer's may also affect the cannabinoid system in the body. Endocannabinoids, naturally occurring chemicals in the body, interact with cannabinoid receptors in the brain and immune system and are responsible for homeostasis. Research shows that Parkinson's disease, Huntington's disease and multiple sclerosis - all neurodegenerative disorders similar to Alzheimer's - reduce cannabinoid system function. These reductions cause many of the symptoms of these illnesses, including anxiety, sleeplessness, and appetite loss.
Cannabis and the Brain
About 150 years ago, medical marijuana was introduced in England to treat a number of conditions, including senile dementia. In 1890, Sir J. Russell Reynolds, physician to Queen Victoria, wrote in Lancet that he "found nothing comparable in utility to a moderate dose of Indian hemp," or marijuana, for treating senile insomnia.
Due to its chemical composition and effects on the brain, cannabis should be studied with regards to Alzheimer's. Recent studies have found that the cannabinoids in marijuana, particularly delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), successfully stimulate appetite, improve sleep and reduce anxiety in Alzheimer's patients.
Cannabis may also help slow disease progression. Iuvone et al. found that CBD reduces the inflammation associated with Alzheimer's. Eubanks, et al., found that THC inhibits the buildup of amyloid plaques, and does so better than the Alzheimer's drugs donepezil and tacrine. They also found that cannabis interferes with neurotransmitter degradation and may halt the formation of tau fiber tangles, which has potential preventative implications.
Research is just beginning regarding the benefits of treating Alzheimer's patients with cannabis, but these early findings are promising and provide direction for further study.