Cannabis and Alzheimers: Promises and Pitfalls

Alzheimer’s disease is a form of dementia affecting primarily seniors and older adults. Symptoms include memory loss, mood and personality changes, and cognitive impairments. One in 10 people over the age of 65 suffer from Alzheimer’s, and the numbers are expected to rise, according to the Alzheimer’s Association. While Alzheimer’s most commonly affects older adults, this debilitating disorder can be a reality for young people too.

Colin, who requested that his last name not be shared, is a 27-year-old disabled veteran from Arizona who is currently pursuing higher education. While serving in the US military, Colin suffered a traumatic brain injury and was subsequently medically discharged. He is suspected to have a disease related to Alzheimer’s, known as chronic traumatic encephalopathy.

Traumatic brain injuries are unfortunately common in military occupations, and they are known to increase the risk of developing Alzheimer’s disease.

“Once I had left the military and began to work with my neurologist and memory specialist, they determined that I had twelve times the normal risk of developing Alzheimer’s, because of my traumatic brain injury and some unique genetic factors,” Colin explains.

“At the time, my memory and functioning was deteriorating. The doctors suspected chronic traumatic encephalopathy, but couldn’t confirm a diagnosis since autopsy is the only way to diagnose it,” he continues.

“Chronic traumatic encephalopathy shares some common symptoms with Alzheimer’s, and it also increases my risk of developing early-onset Alzheimer’s disease.”

Colin’s doctors recommended he make two major lifestyle changes to improve his condition and reduce his risk of developing Alzheimer’s. The first was a medically supervised ketogenic diet, a promising intervention for Alzheimer’s disease. The second? To start using cannabis.

“My neurologist recommended off the record that I try cannabis, as he had seen it help prior patients,” Colin recounts. “The [Veteran’s Affairs] doctors couldn’t officially recommend cannabis for my condition at that time. I don’t know if that has changed.” Luckily, Colin was able to obtain a legal medical cannabis prescription from another doctor, and says his life is better for it.

“Cannabis has helped me immensely, and nearly everyone that I interact with on a daily basis has noticed the return of my memory and daily function. I have been able to return to living independently without someone keeping track of me and my appointments,” says Colin, who is currently pursuing a university degree.

Recent research from Stanford University shows that the endocannabinoid system — a biological system which responds to cannabis and other compounds —may not be functioning normally in the early stages of Alzheimer’s. The researchers are careful to explain their findings don’t imply cannabis is the cure. Still, it’s hard to miss the potential connection between this research and Colin’s experiences.

As promising as that connection may be, we have a long way to go. Most research around cannabis and Alzheimer’s has been conducted on animals. Take this 2012 study, for instance, which found that a synthetic cannabinoid protected rat brains from inflammation caused by amyloid beta. (Amyloid beta is one of the major contributors to the pathophysiology of Alzheimer’s disease). It’s a good start, but so far human studies are few and far between, and the evidence is mixed.

Nurse practitioner Lynn Haslam of Natural Care, a prescription cannabis service for seniors, is cautiously optimistic when it comes to cannabis and Alzheimer’s, and careful to emphasize that the research is still in its preliminary stages. While human trials are limited, she notes that case studies “have reported a decrease in aggression and agitation symptoms.”

“Patients and families are often disturbed by these external symptoms. Having a treatment [such as medical cannabis] that may help to ease and relax the patient without completely sedating them would be helpful,” she explains.

A 2018 study from Sunnybrook Hospital supports Haslam’s interest in cannabis as treatment for Alzheimer’s-related agitation. Researchers there found that the synthetic cannabinoid nabilone was effective at reducing aggression and agitation in Alzheimer’s patients when compared with a placebo. Importantly, researchers also found that caregivers’ stress levels decreased when the patients used the cannabinoid medicine.

However, Haslam is quick to add that there are potential risks doctors and patients should consider before trying cannabis. “We really don’t know how the risk of psychosis plays out in the use of cannabinoids in patients with Alzheimer’s,” she explains. “There is also the risk of further memory loss, which should be considered when weighing the pros and cons of potential cannabinoid treatment.”

The non-psychoactive cannabinoid cannabidiol, or CBD, is also being considered for Alzheimer’s treatment. A 2018 study found that CBD showed antioxidant and neuroprotective effects in a cell model of Alzheimer’s.

CBD is often preferred to THC by patients and healthcare providers alike, because it’s non-psychoactive and often has fewer side effects. Unlike THC, which may increase the risk of developing psychosis, CBD is actually thought to have antipsychotic effects.

What would Haslam say to caregivers who are considering cannabis for their loved one with Alzheimer’s?

“Be sure to start low and go slow when using cannabis in patients with dementia,” she says. “You want to use the minimum necessary dose that addresses symptoms, in order to minimize potential side effects.”

“Think about both the potential risks and benefits,” she adds. “If the patient is at the point where you’re only trying to manage their behaviours, cannabis may be an asset. But it’s still unclear if it can affect the disease progression.”

As more research emerges, healthcare providers will have a better sense of how cannabis may help Alzheimer’s patients. For now, it’s recommended that interested patients and caregivers seek advice from a healthcare provider who is familiar with both Alzheimer’s and cannabis therapy.