Does Marijuana Cause Alzheimer’s?

Alzheimer’s disease has no cure. So, if you or one of your loved ones has Alzheimer’s disease, it’s natural to look for better ways to manage the symptoms of this condition.

Many people also ask, does marijuana cause Alzheimer’s, or could it actually help manage its effects? This guide explores both perspectives — from what causes the disease to how THC and CBD may influence brain health.

We’ll talk about the causes and symptoms of Alzheimer’s disease, how medical marijuana helps Alzheimer’s disease, what strain works best, and so much more.

Symptoms and Causes of Alzheimer’s Disease

The first symptoms of Alzheimer’s vary from person to person; however, there are a few common symptoms to be aware of. 

Loss of memory is the most common symptom of Alzheimer’s disease. Early symptoms include difficulty remembering recent conversations or events. With the progression of the disease, the memory impairment gets worse, and other symptoms begin to surface. 

Alzheimer’s disease causes changes to your brain, which makes it challenging to carry out several functions. It isn’t uncommon for people to have memory lapses once in a while, but the memory lapse which comes with Alzheimer’s disease is persistent and worse. It could lead to getting lost in familiar places, forgetting conversations or events, forgetting the names of family members, and routinely misplacing possessions.

Other common symptoms include:

• Trouble with concentrating and thinking, mainly with abstract concepts like numbers
• Complications with routine activities such as cooking a meal, playing your favorite game
• Forgetting how to perform the seemingly basic tasks like getting dressed
• Mood and behavior changes and complications such as depression, wandering, delusions, mood swings, apathy, and social withdrawal
• Aggression and agitation 

Do you have a family member or loved one with Alzheimer’s? Click here to read MyMove’s Alzheimer’s guide and get your home prepared for caregiving.

Does Marijuana Cause Alzheimer’s Disease?

One of the most common questions people have is: does smoking weed cause Alzheimer’s? The short answer is no, there’s no conclusive scientific evidence that marijuana causes Alzheimer’s disease.

Research has not found a direct causal link between cannabis use and the development of Alzheimer’s. However, studies do show that heavy, long-term marijuana use may affect short-term memory and cognitive function in some users. It’s important to distinguish between temporary memory effects from cannabis use and the progressive neurodegeneration that characterizes Alzheimer’s disease.

That said, some research has raised concerns about marijuana’s potential impact on brain health and Alzheimer’s risk. A 2016 study published in the Journal of Alzheimer’s Disease found that individuals with marijuana use disorders showed significantly reduced blood flow in nearly all areas of the brain compared to healthy controls. Most notably, the hippocampus, the brain region associated with learning and memory and the first area affected by Alzheimer’s, showed the largest reduction in blood flow.

The study, which used brain imaging on 982 marijuana users and 92 healthy controls, revealed:

• Abnormally low blood flow in the right hippocampus during concentration tasks
• Reduced blood flow in virtually every brain region examined
• Concerns that reduced cerebral blood flow could increase vulnerability to Alzheimer’s, since weakened hippocampal blood flow has been associated with the disease

According to the researchers, reduced brain blood flow can decrease oxygen reaching brain cells, potentially causing brain tissue damage. The study’s authors suggested this could represent “damaging influences in the brain, particularly regions important in memory and learning and known to be affected by Alzheimer’s.”

However, it’s important to note:

• This research focused on individuals with marijuana use disorders (heavy, chronic use), not occasional or medical users
• The study showed correlation, not causation — it didn’t prove marijuana directly causes Alzheimer’s
• This was a 2016 study, and more recent research has explored cannabinoids’ potential protective effects
• The researchers themselves called for further studies to pinpoint “actual risk levels of dementia” for marijuana users

Most current research focuses on whether cannabinoids like THC and CBD might actually protect the brain or slow Alzheimer’s progression, rather than cause it. That said, moderation and consumption method matter, which we’ll explore in more detail below. If you’re considering medical marijuana for Alzheimer’s symptoms, it’s essential to work with a qualified physician who can help you weigh the potential benefits and risks.

Does Weed Help with Alzheimer’s Symptoms?

An increasing body of research suggests that marijuana and Alzheimer’s patients may benefit from cannabinoid therapy, particularly for managing difficult symptoms like agitation, aggression, and sleep disturbances.

According to a preclinical study, small doses of tetrahydrocannabinol (THC), a chemical found in marijuana, can slow the production of beta-amyloid proteins. Beta-amyloid proteins are one of the key contributors to the progression of Alzheimer’s.

Another study also found that THC and some other compounds present in marijuana can reduce the amount of beta-amyloid proteins found in the brain. According to this study, when beta-amyloid proteins get exposed to THC, it reduces their levels in the brain, stops the inflammatory response from the nerve cells caused by the beta-amyloid proteins, and allows the nerve cells to survive. According to the United Kingdom’s Alzheimer’s society, cannabis or its components can counteract symptoms such as agitation and aggression.

Medical marijuana may help with:

• Reducing agitation and aggression
• Improving sleep quality
• Decreasing inflammation in brain tissue
• Stimulating appetite
• Managing mood-related symptoms like depression

However, the Alzheimer’s Association in the United States has stated that marijuana is still an untested drug for Alzheimer’s disease. Its potential effectiveness and safety profile have not been thoroughly evaluated in clinical trials in people with or at risk for Alzheimer’s. Researchers have also noted that further research still needs to be conducted on the potential of medical marijuana for treating Alzheimer’s disease.

THC vs. CBD: Which Helps Alzheimer’s Patients More?

When exploring marijuana and Alzheimer’s disease, it’s important to understand the difference between THC and CBD — the two primary cannabinoids in cannabis.

THC and Alzheimer’s

THC (tetrahydrocannabinol) is the psychoactive compound in marijuana. Research suggests that:

• Small doses may reduce beta-amyloid plaque buildup
• It may help with agitation and behavioral symptoms
• It can stimulate appetite, which is helpful for patients who lose interest in eating
• However, THC does produce intoxicating effects, which may not be ideal for all patients

A groundbreaking 2024 clinical trial led by Johns Hopkins University School of Medicine and Tufts University School of Medicine provided strong evidence for THC’s effectiveness in treating Alzheimer’s agitation. The eight-year study, which included 75 patients with severe Alzheimer’s agitation across five clinical sites, found that:

• Dronabinol (an FDA-approved synthetic form of THC) reduced agitation by an average of 30% after just three weeks of treatment
• Patients received 5 milligrams of dronabinol in pill form twice daily
• The medication was well-tolerated compared to current treatments like antipsychotics
• It produced similar calming effects to existing medications without adverse results such as delirium or seizures
• Results were measured using standardized agitation scales and showed significant improvement

According to the researchers, “agitation is one of the most distressing symptoms of Alzheimer’s dementia,” and dronabinol represents an important advancement in treatment. The study noted that agitation (not memory loss) is often what drives individuals with dementia to emergency departments and long-term care facilities.

This FDA-approved synthetic THC offers a controlled, measurable approach to managing one of Alzheimer’s most challenging symptoms, with the potential to reduce healthcare costs and positively impact caregivers’ mental and physical health.

CBD Oil and Alzheimer’s Disease

CBD oil does not have the intoxicating properties of THC, and it can help reduce the damage caused by inflammation and improve the mood of Alzheimer’s patients. Cannabidiol products like oils help to boost cognitive activity and repair brain cells. Additionally, it protects Alzheimer’s patients from neurotoxicity and minimizes oxidative stress.

A study found that a two-week course of high doses of CBD helped restore the function of two proteins in the body, which reduced the build-up of beta-amyloid proteins and improved cognition in an experimental model of early-onset familial Alzheimer’s. 

Some studies have also shown that the symptoms of behavioral and psychological symptoms of dementia (BPSD) decreased with CBD.

Also, in recent research, CBD has been shown to help reduce the impact of inflammation, oxygen build-up, and brain cells’ death. In another study, researchers increased IL-33 and TREM2 in the brain and maintained cognitive functions by eliminating the dead cells and clearing the beta-amyloid plaque associated with Alzheimer’s. (It is worth noting researchers conducted this test on mice.) 

After a regular injection of CBD in the mice with Alzheimer’s, they noticed a significant change in their ability to tell the difference between objects. Though animal-tested, the results proved significantly promising for people with Alzheimer’s as well. And, since CBD cannot get you high, it’s an excellent option for those looking to avoid THC. 

The Bottom Line: Many Alzheimer’s patients and caregivers find that a combination of both THC and CBD offers the most comprehensive symptom relief, though individual responses vary.

Can Smoking Weed Make Alzheimer’s Worse?

While cannabinoids themselves may offer therapeutic benefits, the method of consumption matters — especially when it comes to brain health.

Smoking marijuana involves inhaling combusted plant material, which can:

• Cause inflammation in the lungs and potentially the brain
• Introduce toxins and carcinogens
• Reduce oxygen flow, which isn’t ideal for cognitive health

For Alzheimer’s patients, alternative consumption methods may be safer and more effective:

• Tinctures (sublingual drops)
• Edibles (gummies, capsules)
• Vaporizers (lower temperature, less combustion)
• Topical applications

These methods deliver cannabinoids without the potential harms associated with smoke inhalation, making them better options for older adults and those with compromised respiratory or cognitive function.

Marijuana and Alzheimer’s Research: What We Know So Far

The relationship between marijuana and Alzheimer’s disease is an active area of scientific investigation. Here’s what current research tells us:

Scientists have made some encouraging discoveries in laboratory settings. A 2019 research review looked at nine different studies on marijuana for Alzheimer’s and found promising results when testing CBD on brain cells:

• Protected brain cells from the toxic proteins that cause Alzheimer’s damage
• Helped more brain cells survive and stay healthy
• Reduced harmful inflammation and cell damage
• Prevented the buildup of problematic proteins that tangle up in Alzheimer’s patients’ brains
• Helped protect memory and thinking abilities

Beyond the laboratory, researchers tested CBD on mice with Alzheimer’s-like symptoms and saw even more benefits:

• Reduced brain swelling and inflammation
• Actually helped grow new brain cells in the memory center of the brain (the hippocampus)
• Calmed down the brain’s inflammatory response

Perhaps most importantly, studies found that using THC and CBD together worked better than using either one alone. In mice with Alzheimer’s, the combination:

• Improved memory and recognition abilities
• Reduced the harmful protein clumps in the brain
• Lowered inflammation throughout the brain
• Helped balance brain chemistry in ways that support thinking and memory

According to researchers, “using CBD and THC together could be more useful than using CBD or THC alone” for treating Alzheimer’s symptoms.

While these findings are exciting, there are important things to keep in mind:

• Most of this research was done in laboratories or on animals, not on actual Alzheimer’s patients
• We don’t yet know the ideal dosage or the perfect mix of THC to CBD
• More studies on real patients are needed to confirm these benefits
• Everyone responds differently to cannabis
• Scientists are still figuring out the best way to use medical marijuana for Alzheimer’s

The bottom line: Research suggests marijuana has real potential for helping with Alzheimer’s, especially for managing symptoms like agitation. The 2024 Johns Hopkins study proving that synthetic THC reduces agitation by 30% is a major step forward. However, we’re still learning exactly how to use it most effectively. In states where medical marijuana is legal for Alzheimer’s, many patients and their doctors are already finding it helpful.

Indica or Sativa for Alzheimer’s Disease?

The preferred strain to use for Alzheimer’s disease seems to depend on the most common symptoms you experience. Indicas and sativas both present their own unique characteristics, though it mainly depends on the strain and terpenes.

Sativa strains enhance your cognitive function, and so they’re helpful if you want a boost in stimulation and be fully engaged in conversations. If you find that your Alzheimer’s has left you depressed and unmotivated, potent sativa strains are lovely for putting a smile on your face and a spring back in your step.

If your symptoms revolve more around the inability to sleep or loss of appetite, the indica strain would be best. Indicas help you sleep better, improve your eating patterns, and provide you a nice dose of full-body relaxation. For those who are often uptight and stressed surrounding Alzheimer’s symptoms, indicas may be the decompression you need.

A hybrid of indica-sativa is also a great alternative because it offers you the benefits of both indicas and sativas. They’re the best of both worlds!

So, when looking for the right medical marijuana strain for Alzheimer’s, take a step back and consider your symptoms. Then, research some strains at your local dispensary and see what kind of effects they tend to produce. This is a great way to see if they help with what you require.