Alzheimer’s disease takes a huge toll on millions of families every year, and presents a huge burden on health care systems. Family members are not only burdened with health care costs that often include long-term care and hospice, but the emotional toll it takes is unquantifiable. What is shocking, is that despite years of promising leads, scientists have yet to develop effective treatments to prevent, delay or cure Alzheimer’s.
Consider this sobering statistic: from 2002 to 2012 — a decade — 244 Alzheimer's drugs were evaluated through 413 different trials (with 83 making it to a Phase III trial). According to the journal of Alzheimer's Research & Therapy, during this time, just one drug — yes, you read correctly! — was approved by the FDA.
That puts Alzheimer's disease drug candidates at top of drug development failure rates. 99.6% of Alzheimer’s disease drugs fail; in contrast, 81% of cancer drugs fail.
In Scientific American, the UK government’s appointed World Dementia Envoy, Dennis Gillings, provides an ominous warning: “Dementia is a ticking bomb costing the global economy £350 billion and yet progress with research is achingly slow.” Gillings argues that we need to “free up regulation so that we can test ground-breaking new drugs.”
Could it be that a cure for Alzheimer's already exists, and “Big Pharma” is just looking in the wrong place? In fact, could a plant — cannabis — provide a cure for Alzheimer’s? Growing evidence suggests it’s certainly possible.
In this article, we’ll examine what exactly Alzheimer’s disease is, what are its possible causes, and what science has to say about cannabis and its potential to provide more effective treatments for Alzheimer’s.
What is Alzheimer’s Disease?
Alzheimer’s disease is commonly characterized as progressive brain disorder causing patients to experience memory loss and disruption in their ability to perform everyday tasks. According to the National Institutes of Health, Alzheimer’s Disease is the leading cause of dementia and a leading cause of death, affecting more than five million Americans — a number expected to triple over the next 50 years.
Remarkably, one in three seniors will die from dementia, most commonly Alzheimer’s. In 2013, the cost to treat Alzheimer’s reached $203 billion in the U.S. alone!
What Causes Alzheimer's Disease?
The precise causes of Alzheimer’s Disease are not well understood, however, one of the primary neuropathological markers of Alzheimer's disease is amyloid-beta peptide (A?) deposits in areas of the brain important for memory and cognition. Notably, researchers have demonstrated that the most prominent cannabinoid in cannabis — delta-9-tetrahydrocannabinol (commonly known as THC) — inhibits the proliferation of A? deposits. (Elevated A? levels are associated with cognitive impairments influencing learning, memory, personality, and social skills, and over time, diminishes one’s life expectancy and overall quality of life.)
Alzheimer’s disease has also been associated with:
- Neuroinflammation: inflammation of the nervous tissue
- Oxidative stress: an imbalance between the production of free radicals and the body’s ability to detoxify their harmful effects
- Excitotoxicity: the process by which neurons are killed or damaged by overactivation of glutamate receptors
The Government Agrees: Cannabinoids Could Help Treat Alzheimer’s Disease
Our own federal government has long recognized that cannabinoids could be useful to prevent or treat neurodegenerative diseases — such as Alzheimer’s disease. In fact, in the 1990s, researchers at the U.S. Department of Health and Human Services (HHS) studied cannabinoids as part of an effort to develop a new class of antioxidant and neuroprotective drugs that could be used to treat a wide array of conditions. They even claimed that administering a patient “a therapeutically effective amount of a cannabinoid to protect against oxidative injury to the central nervous system,” could potentially “prevent or treat neurodegenerative diseases.”
The researchers were particularly interested in the second most prominent cannabinoid in cannabis, cannabidiol (CBD), because CBD doesn’t produce toxicity or psychoactive effects — even in large doses (e.g. 700 mg/day). They cite research claiming, “no signs of toxicity or serious side effects have been observed following chronic administration of cannabidiol to healthy volunteers.”
Based on the government researchers’ findings, in 1999, the federal government filed for a patent on “cannabinoids as antioxidants and neuroprotectants.” Describing their “invention,” as useful in “preventing, arresting, or treating neurological damage in Parkinson's disease, Alzheimer's disease and HIV dementia,” they were ultimately granted US Patent 6630507 in 2003.
According to the patent, the government also ascribed the following benefits of cannabinoids:
- Cannabinoids have been found to have antioxidant properties, unrelated to NMDA receptor antagonism. This new found property makes cannabinoids useful in the treatment and prophylaxis of wide variety of oxidation associated diseases, such as ischemic, age-related, inflammatory and autoimmune diseases.
- Cannabinoids are found to have particular application as neuroprotectants, for example in limiting neurological damage following ischemic insults, such as stroke and trauma, or in the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease [emphasis mine] and HIV dementia.
The Federal Government’s Hypocrisy
Does it seem ironic — nay, hypocritical — that on one hand the federal government would fight medical marijuana, while at the same time, trying to patent it? It does anger many people who find their actions typify governmental hypocrisy. No doubt, the government doesn’t seem to be particularly interested in whole plant cannabis. They’re interested in pharmacological preparations of cannabis. But, of course, this lends merit to conspiratorial suspicions by many individuals in the medical cannabis community (and the general public) who believe the government is in bed with “Big Pharma.”
John Crudele, a journalist whose wife suffered from multiple sclerosis for nearly a decade before dying, was particularly irate. On the government’s hypocrisy, Crudele wrote an article in the New York Post expressing his outrage. “Just so you understand me, this is the same US government that has been fighting the use of marijuana as a drug. Yet its own scientists were claiming a decade ago that marijuana had been effective against a number of diseases.” Crudele continues, “You won’t really appreciate what I’m talking about until someone you love might be helped by medical marijuana. But you will probably never understand just how angry I am after finding out about Patent No. 6,630,507.”
Crudele continues, “Despite a track record of thousands of years, Americans are still debating whether we should allow sick people to relieve symptoms of nausea and pain with pot because marijuana may sometimes end up in the wrong hands.”
How Might Cannabis Halt or Slow Progression of Alzheimer’s?
THC inhibits amyloid plaque build-up — the primary marker of Alzheimer’s
One of the primary pathological markers of Alzheimer's is the buildup of amyloid plaques — specifically the amyloid beta (A?) peptide — in areas of the brain important for memory and cognition. Accumulating research has found THC can halt or slow Alzheimer’s progression by dampening the synthesis of A? peptides and amyloid plaque build-up. Researchers from San Diego, California first identified the molecular link between THC and Alzheimer's disease pathology in 2008. According to Kim Janda, Ph.D, one of the lead investigators:
"When we investigated the power of THC to inhibit the aggregation of beta-amyloid, we found that THC was a very effective inhibitor of acetylcholinesterase. In addition to propidium, we also found that THC was considerably more effective than two of the approved drugs for Alzheimer's disease treatment, donepezil (Aricept ®) and tacrine (Cognex ®), which reduced amyloid aggregation by only 22 percent and 7 percent, respectively, at twice the concentration used in our studies. Our results are conclusive enough to warrant further investigation." Notably, the researchers found that at the low concentrations tested, THC exhibited no toxicity.
Publishing a study in the Journal of Alzheimer’s Disease, University of South Florida researchers provided similar conclusions. They found THC could enhance mitochondrial function and limit cognitive impairment by lowering A? peptide levels. Researchers wrote: "[W]e believe that THC has therapeutic value, and that at low enough doses, the potential benefits strongly prevail over the risks associated with THC and memory impairment." The researchers also noted that while advancements have been made in the field, no treatments specifically targeting A?-peptide levels have been approved by the FDA. THC, they believe could address the need for more effective Alzheimer’s treatments that inhibit A? synthesis and proliferation.
Cannabis is anti-inflammatory and neuroprotective
In another study, researchers from the Salk Institute in La Jolla, California also found that THC and other compounds found in cannabis can not only reduce the amount of A? peptides in the brain, but stop the inflammatory response from the nerve cells caused by A? peptides while allowing the nerve cells to survive. Salk Professor David Schubert, the senior author of the paper notes: “Although other studies have offered evidence that cannabinoids might be neuroprotective against the symptoms of Alzheimer’s, we believe our study is the first to demonstrate that cannabinoids affect both inflammation and amyloid beta accumulation in nerve cells.”
Antonio Currais, a postdoctoral researcher in Schubert’s laboratory and a contributing author to the study notes: “Inflammation within the brain is a major component of the damage associated with Alzheimer’s disease, but it has always been assumed that this response was coming from immune-like cells in the brain, not the nerve cells themselves,” reports Currais. “When we were able to identify the molecular basis of the inflammatory response to amyloid beta, it became clear that THC-like compounds that the nerve cells make themselves may be involved in protecting the cells from dying.”
But, how could cannabis, which is thought to impair cognitive function (at least acutely), actually be a neuroprotectant? In a 2012 research review, Dr. Andras Bilkei-Gorzo explains:
“At first sight, it is striking that cannabinoid agonists, substances known to impair cognitive functions, could be beneficial in neurodegenerative cognitive disorders. However, [we found] cannabinoid receptor activation could reduce oxidative stress and excitotoxicity, suppress neuroinflammatory processes and thus alleviate the symptoms of neurodegenerative motor and cognitive diseases.”
Can Medical Marijuana be Used to Treat Dementia Symptoms?
Symptoms from Alzheimer’s related dementia include aggression, depression, anxiety, hallucinations, and insomnia. Researchers from Israel published a study in The Journal of Alzheimer’s Disease concluding cannabis extract containing THC can relieve Alzheimer’s symptoms. Researchers observed effects of medical cannabis on patients suffering from Alzheimer’s over the course of four weeks. Researchers concluded: “Adding medical cannabis oil to Alzheimer’s patients’ pharmacotherapy is a safe and promising treatment option.”
Do you have a loved one who suffers from Alzheimer’s Disease? What do you think about the prospect of using medical cannabis to treat Alzheimer’s and dementia symptoms? Share your thoughts in the comments section below.