Can Marijuana Help With Or Prevent Alzheimer's Disease?

Medically reviewed by Julie Dodson, MA
Updated June 14, 2024by BetterHelp Editorial Team
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Cannabis, also referred to as marijuana, may still be considered the “controversial kid on the block” in the medical community. However, there's no denying that, over the years, it has gradually gained traction as a possible treatment for a number of chronic illnesses and other diseases, including Alzheimer's. Hundreds of studies have been conducted, most of them in laboratories and on animals, and many of the results are promising. Hemp and cannabis, or marijuana, are plants from the species Cannabis Sativa. They have different uses and applications, but for this article, we will focus on marijuana/cannabis only. Let's look at the medicinal properties of this plant, and how it can help with the management and treatment of Alzheimer's disease (AD).

So…can marijuana help with alzheimer's?

In short, yes, research suggests that marijuana can help with Alzheimer’s disease. In fact, one study published in the Journal of Alzheimer's Disease concluded that "…THC could be a potential treatment option for Alzheimer's disease through multiple functions and pathways."

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THC, or tetrahydrocannabinol, is a cannabis-derived compound or chemical. There are over a hundred active compounds found in the plant, and they are referred to as cannabinoids. However, THC and cannabidiol (CBD) are the most well-researched cannabinoids. At this point, they seem to be the two with the most health benefits, but recent studies indicate that there may be others.

In one study, researchers discovered that minute doses of THC could slow down the production of amyloid-beta (Aβ) protein in the brain. Aβ protein has been found to be the main component in toxic plaques that grow in and clog the brains of Alzheimer's patients. They are also associated with brain-cell death, which causes the cognitive decline characteristic of AD. This process seems to start long before the first symptoms of the disease make their appearance.

Another 2016 California-based, in-vitro study conducted by the Salk Institute for Biological Studies demonstrated that THC, among other cannabinoids, may not just slow down but even remove a significant amount of Aβ protein from brain cells.

The study also showed that cannabinoids could counteract inflammation in nerve cells and prevent associated brain cell death. In this sense, THC may have a defensive role to play in the prevention of Alzheimer's and other brain degenerative diseases. 

According to Antonio Currais, post-PhD researcher and first author on the paper, this is an important finding, stating: "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. 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 safeguarding the cells from dying."

He makes a noteworthy point - "THC-like compounds that the nerve cells make themselves." This brings us to one of the fascinating aspects of cannabis and the plant's health benefits to the human body.

How does it work?


Despite the stigma that has historically surrounded marijuana use, our bodies curiously seem to be designed to benefit from the compounds found within its plant material. 

The human body contains what’s known as the endogenous cannabinoid (or endocannabinoid) system, which serves several important functions regardless of whether a person uses marijuana or not. It was named after the plant that led to its discovery, and one doctor, Dr. Bradley Elgar, called this "one of the most important physiologic systems involved in establishing and maintaining human health." For this reason, it is likely worth investigating, and not only for the treatment or management of Alzheimer's disease.

The endocannabinoid system has two kinds of cannabinoid receptors in cells found throughout the body: CB1 and CB2 receptors. These cells are mostly concentrated in the brain, the central nervous system, the immune system, and the digestive system. Cannabinoid actions and functions are superbly complex, but they can be understood as a bridge between bodily processes and the mind. 

THC for Alzheimer's

As mentioned, two marijuana-derived cannabinoids (CBD and THC) have been well studied, and they have diverse roles within the body. THC is the compound best known for binding with CB1 receptors and causing the well-known “high” that can accompany marijuana use. THC also seems to have indications for the treatment of neuropathic pain, nausea, anxiety, and anorexia.

In 2015, a Netherlands-based randomized, double-blind, placebo-controlled study was conducted to determine the effects of THC on dementia-related symptoms such as aggression, anxiety, depression, insomnia, and hallucinations. Alzheimer's disease is one form of dementia. It was found that the twenty-four patients who received 1.2 mg of THC three times a day showed no difference compared to patients taking a placebo.

On the other hand, in another study, THC seemed to have the opposite effect. In 2016, another group of researchers conducted a small study on this cannabinoid's effect on dementia-related symptoms. Their finding was that THC in medical cannabis oil (MCO) significantly decreased delusions, agitation or aggression, irritability, apathy, sleep, and even caregiver distress. The doctors stated: "Adding MCO to AD patients' pharmacotherapy is safe and a promising treatment option."

Why these diverse findings? One reason could be that the first study may have been conducted with pure THC, while in the other, the patients ingested medical cannabis oil. Why is this important? While THC on its own can be impressive, when working together with cannabidiol (CBD) and other compounds found in whole-plant oil, its effects are amplified. This is called the “entourage effect.”

CBD for Alzheimer's

Cannabidiol is one of over 100 active cannabinoids in marijuana, and it differs from THC in many ways. The most prominent difference is that ingesting pure CBD will not give you the hallmark feelings of euphoria and intoxication. It binds to both CB1 and CB2 cell receptors in the body, but its chemical and metabolic action differs greatly from THC's. Interestingly, it seems to inhibit THC's psychoactive effects, but so far, CBD has been best studied for its effects on epilepsy.

In fact, a new anticonvulsant drug with CBD may soon be approved by the FDA. The industry speculates that this may open doors for more robust, human-subject clinical research on the benefits of CBD and increase the availability of cannabis as a medicine.

CBD has also demonstrated strong anti-inflammatory and antioxidant properties in many animal studies. In a 2017 review of the latter, the researchers concluded that all the studies provide "proof of principle" that CBD, and possibly CBD with THC, are "valid candidates" for new Alzheimer's therapies. They suggested that further investigation should address the long-term effects of CBD and evaluate the mechanisms involved in its therapeutic effects.

Remember amyloid-beta (Aβ)? In a 2005 study performed on mice, CBD's strong action against Aβ-associated neuroinflammation was confirmed. Again, the researchers stressed that this could offer a novel treatment not only to manage Alzheimer's but perhaps to reverse it.

But isn't cannabis/marijuana bad for you?

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Marijuana has historically been subject to a high amount of stigma and misconception, particularly due to its association with communities of color and those with lower socioeconomic statuses. Likewise, THC is often demonized for the effects it can cause, which contributes to many labelling it as a “gateway drug” that leads to the use of more dangerous, illicit substances. 

In reality, marijuana use is not necessarily bad for the body. Experts believe most recreational and medicinal marijuana users never progress to use the "harder" substances, and so-called “cross-sensitization” is not unique to marijuana. The National Institute on Drug Abuse states: "Alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances." How potentially harmful marijuana is largely depends on the person.

Therefore, dismissing marijuana or cannabis to treat or prevent Alzheimer's disease simply based on its potential to be addictive may be unnecessary, and perhaps even unwise. Much more clinically and statistically relevant study is needed before cannabis will be fully accepted in the medical and general community, but its potential value is, by now, almost indisputable.

Still, despite the many potential benefits of cannabis, it’s generally best for any person who has dementia or Alzheimer's disease to consult a doctor before adding things like CBD oil or other products to their routine. 

Need help?

If you’re living with Alzheimer’s disease, caring for someone who is, or simply would like to receive professional support, it may be beneficial to consider seeking the guidance of a therapist who understands your experiences. When combined with other forms of treatment, therapy can be highly beneficial for managing stress, overcoming challenges, and finding a way to make peace with your symptoms.

Resources like online therapy can be an especially great way to get started. You don’t have to leave the comfort of your own home to avail of the care you may need, and by avoiding the need to go to and from in-person appointments, you may be able to save both time and money.

Additionally, online therapy is known to produce real change in the lives of those who pursue it. A recent review of 17 studies focused on online cognitive behavioral therapy found that it could be just as effective as in-person options for treating mental health symptoms, specifically those related to depression. It also noted that online therapy was generally more cost-effective for clients than face-to-face treatment.


Marijuana and the compounds found within it, specifically THC and CBD, may be beneficial for treating and preventing Alzheimer’s disease, at least according to current research. More studies are likely needed to determine what sort of treatment options might be the most effective, but overall, it seems that marijuana may offer benefits for a variety of people and conditions.
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