Cannabis May Help Rejuvenate the Aging Brain and Ward Off Dementia

cannabis for dementia

Story at-a-glance -

  • THC has a beneficial influence on the aging brain, reversing the aging process and improving cognitive function, raising the possibility it might be useful for the treatment of dementia in the elderly
  • 18-month-old mice given THC at 2, 12 and 18 months demonstrated cognitive skills equal to 2-month-old controls, while the placebo group suffered cognitive deterioration associated with aging
  • Previous research has also shown low-dose THC directly impedes buildup of beta amyloid plaque in the brain (a hallmark of Alzheimer’s) and enhances mitochondrial function in the brain

By Dr. Mercola

Regardless of your views on the pros and cons of recreational marijuana, the body of scientific evidence about its medicinal value is getting more compelling as additional research is done. The cannabinoids in cannabis — cannabidiol (CBD) and tetrahydrocannabinol (THC) — interact with your body by way of naturally-occurring cannabinoid receptors embedded in cell membranes throughout your body.

In fact, scientists now believe the endocannabinoid system may represent the most widespread receptor system in your body.1 There are cannabinoid receptors in your brain, lungs, liver, kidneys, immune system and more, and both the therapeutic and psychoactive properties of marijuana occur when a cannabinoid activates a cannabinoid receptor.

Your body actually makes its own cannabinoids, similar to those found in marijuana, albeit in much smaller quantities than you get from the plant. The fact that your body is replete with cannabinoid receptors, key to so many biological functions, is why there's such enormous medical potential for cannabis.

The whole plant also contains terpenes that have medicinal properties. More often than not, medicinal marijuana is made from plants bred to have high CBD and low THC content. While THC has psychoactive activity that can make you feel "stoned," CBD has no psychoactive properties. However, recent research shows THC should not be written off completely just because it's psychoactive. It has valuable therapeutic potential in its own right.

THC May Reverse Aging Process in the Brain

According to recent animal research,2 THC has a beneficial influence on the aging brain.3,4 Rather than dulling or impairing cognition, THC appears to reverse the aging process and improve mental processes, raising the possibility it might be useful for the treatment of dementia in the elderly.5

To test the hypothesis, mice were given a small daily dose of THC over the course of one month at the age of 2 months, 12 months and again at 18 months of age. It is important to understand that mice typically live until 2 years old. The dose was small enough to avoid any psychoactive effects.

Tests assessed the animals' learning, memory, orientation and recognition skills. Interestingly, 18-month-old mice given THC demonstrated cognitive skills equal to 2-month-old controls, while the placebo group suffered cognitive deterioration associated with normal aging.

According to one of the authors, neurobiology professor Andreas Zimmer, University of Bonn, "The treatment completely reversed the loss of performance in the old animals. We repeated these experiments many times. It's a very robust and profound effect." Even more remarkable, gene activity and the molecular profile in the brain tissue was that of much younger animals. Specifically, neurons in the hippocampus grew more synaptic spines — points of contact necessary for communication between neurons.

According to Zimmer, the THC appeared to have "turned back the molecular clock" in the THC-treated animals. (Previous research has also shown that the brain ages much faster in mice who do not have functional receptors for THC, suggesting THC may be involved in the regulation of the aging process.6) The team is now planning tests to see if the same holds true in human subjects.

Cannabinoids Maintain Homeostasis

Your endocannabinoid system has homeostatic properties, meaning it helps balance your body's response to stress. This helps explain some of the individual variations in response to cannabis.

In your brain, cannabinoids modulate neural activity. In younger people, in which endogenous cannabinoids are already plentiful, cannabis will not have the same effect as in older people, in whom activity of the endogenous cannabinoid system is much lower. The effects of THC in particular appear to vary significantly depending on age. As noted by Forbes:7

"[Y]ounger animals excelled at the tests when 'sober' but tended to struggle significantly under the influence of THC. 'Mature' and 'old' mice, on the other hand, struggled with tasks as consistent with their brain ages at first, but saw a huge increase in performance with THC infusions …

Overall, the results seem to support researchers' belief that the benefits for older mice are a result of stimulating the brain's endocannabinoid system, a biochemical pathway in both mice and human that grows less active over time."

In other words, in young mice (and probably people as well), THC can easily have an overly stimulating effect, resulting in a decline in memory and learning (albeit temporary, while under the influence). In older mice, a small amount of THC basically restored levels to a more youthful optimum.

Similarly, one of the reasons cannabis is so effective for seizures is because of this ability to regulate neuronal activity and reestablish homeostasis. If there's too much neuronal activity, the cannabis suppresses activity, and if activity is low, it raises it.

Cannabis for Pain

Polls show older Americans are becoming increasingly converted to marijuana use.8 Between 2006 and 2013, use among 50- to 64-year-olds rose by 60 percent. Among seniors over 65, use jumped by 250 percent.9 Pain and sleep are among the most commonly cited complaints for which medicinal marijuana is taken.

Considering the high risk of lethal consequences of opioid painkillers and sleeping pills, medical marijuana is a godsend. It's really unfortunate that we've been so successfully indoctrinated to view marijuana as a dangerous gateway drug that will lead to illicit drug use.

The reality is that prescription drugs have far greater potential to turn you into a "junkie." Legal drug addiction is also taking lives in record numbers. There's absolutely no doubt that cannabis is safer than most prescription drugs — especially opioids. As noted by Dr. Margaret Gedde, an award-winning Stanford-trained pathologist and founder of Gedde Whole Health, there's enough scientific data to compare the side effects of cannabis against the known toxicities of many drugs currently in use.

This includes liver and kidney toxicity, gastrointestinal damage, nerve damage and, of course, death. Cannabidiol has no toxicity and it's virtually impossible to die from marijuana. It's also self-limiting, as excessive doses of THC will provoke anxiety, paranoia and nausea.

Such side effects will disappear as the drug dissipates from your system without resulting in permanent harm, but it'll make you think twice about taking such a high dose again. Make the same mistake with an opioid, and chances are you'll end up in the morgue.

Cannabis Often Works Where Drugs Fail

Gedde also notes that cannabis products often work when other medications fail, so not only are they safer, they also tend to provide greater efficacy.

In 2010, the Center for Medical Cannabis Research (CMCR) released a report10 on 14 clinical studies about the use of marijuana for pain, most of which were FDA-approved, double-blind and placebo-controlled. The report revealed that marijuana not only controls pain, but in many cases, it does so better than pharmaceutical alternatives.

When cannabis is inhaled, smoked or vaporized, its effects are rapid and short-lasting. Orally, it's the most unpredictable and delayed. When ingesting it, it can take up to two hours to take effect, but if dosed appropriately, you can achieve once-a-day dosing with an edible medicine.

As for the psychoactive effects of THC, a dose of 10 milligram (mg) or more of an oral (edible) THC product is required to produce a high.11 Taking 50 to 100 mg of oral THC could result in a serious case of paranoia, with or without nausea and vomiting.

Other Common Ailments Treated With Cannabis

Aside from pain and sleep, other common ailments being treated with cannabis include:

Degenerative neurological disorders such as dystonia

Multiple sclerosis and other autoimmune issues

Parkinson's disease

Mood disorders, anxiety and post-traumatic distress disorder (PTSD).12,13 Marijuana suppresses dream recall, so for those having nightmares, it can be transformative. Marijuana is also reported to help individuals stay focused in the present, which is beneficial for those experiencing flashbacks.

In January 2017, the Multidisciplinary Association for Psychedelic Studies14 began the first federally-approved study in which the subjects — combat veterans diagnosed with PTSD — will ingest marijuana by smoking. It's also the first whole-plant marijuana study, as opposed to an extract

Seizure disorders such as Dravet syndrome,15 also known as Severe Myoclonic Epilepsy in Infancy, a form of intractable, life-threatening epilepsy in which a child can suffer upward of 100 seizures a day. Certain varieties of cannabis offer the only real hope for children with this type of disorder, as Dravet syndrome does not respond well to standard epilepsy drugs

Cannabis even appears to be a natural chemotherapy agent. Dozens of studies point to marijuana's effectiveness against many different types of cancer, including brain cancer, breast, prostate, lung, thyroid, colon and pituitary cancer, melanoma and leukemia.

It fights cancer via at least two mechanisms, making it difficult for a cancer to grow and spread. It's proapoptotic, meaning it triggers apoptosis (cellular suicide) of cancer cells while leaving healthy cells untouched, and antiangiogenic, meaning it cuts off a tumor's blood supply.

Could Cannabis Offer New Hope for Alzheimer's Patients?

Getting back to where we started, with THC rejuvenating the aging brain, this actually wasn't the first time THC has been shown to provide benefits against dementia.

In a 2014 study, researchers at the University of South Florida and Thomas Jefferson University found that low-dose THC directly impedes the buildup of beta amyloid plaque in the brain,16,17 which is associated with the development of Alzheimer's, and unlike so many pharmaceutical drugs, it produces no toxicity. THC was also found to enhance mitochondrial function in the brain. Lead author and neuroscientist Chuanhai Cao, Ph.D., wrote:

"THC is known to be a potent antioxidant with neuroprotective properties, but this is the first report that the compound directly affects Alzheimer's pathology by decreasing amyloid beta levels, inhibiting its aggregation and enhancing mitochondrial function."

Cannabis is also known to reduce some of the non-memory-related symptoms typically experienced by Alzheimer's sufferers, including anxiety, irritability and rage,18 so cannabis may well have multiple benefits for those with dementia and Alzheimer's.

Where to Find Reputable Information About Medical Cannabis, Its Uses and Benefits

If the idea of using medical cannabis (provided it's legal in your state) still makes you cringe, I recommend delving deeper into the research to educate yourself on the matter, especially if your alternative is an opioid pain pill or some other dangerous drug.

One reputable source where you can find research relating to the use of cannabis is cancer.gov.19,20 This is the U.S. government's site on cancer. Simply enter "cannabis" into the search bar. You can also peruse the medical literature through PubMed,21 which is a public resource (again, simply enter "cannabis" or related terms into the search bar).

The Journal of Pain,22 a publication by the American Pain Society, has a long list of studies on the pain-relieving effects of cannabis and would certainly seem worth the effort for anyone with chronic pain to utilize.

According to the National Institute on Drug Abuse,23 which also has information relating to the medicinal aspects of marijuana, preclinical and clinical trials are underway to test marijuana and various extracts for the treatment of a number of diseases, including autoimmune diseases such as multiple sclerosis and Alzheimer's disease, inflammation, pain and mental disorders.

I also recommend listening to my previous interviews with Gedde and Dr. Allan Frankel, in which they discuss the clinical benefits of cannabis. Frankel is a board-certified internist in California who has treated patients with medical cannabis for the past decade.

Awareness is starting to shift, and many are now starting to recognize the medical value of cannabis. Even the former U.S. Surgeon General has spoken out in favor of medical marijuana. His statement echoes a growing sentiment in the medical and scientific communities that the health benefits of marijuana should no longer be ignored. Murthy was replaced this month by his deputy, Rear Adm. Sylvia Trent-Adams.

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