Cannabis and Cognition

Dementia seems to be touching more and more of us these days: patients, families, caregivers, and practitioners. There are now nearly 6 million people in the U.S. with Alzheimer’s disease (AD) and related dementias, and that number is projected to increase substantially in the coming decades.

Though there is still much mystery as to why AD occurs, what is quite clear is that specific regions of the brain are affected. And the vast devastation occurring in those locations often leads to memory loss, cognitive impairment, and unwanted behavior. These behaviors include agitation, aggression, and insomnia. In addition, there are changes involving appetite, motivation, planning, social behavior, language, personality, mood, swallowing, and gait. (1)

Current treatment modalities either attempt to maintain levels of acetylcholine (an important neurotransmitter involved with cognition whose concentrations decrease in AD and other dementias); attempt to modify the underlying disease’s advancement; or calm the agitation and help with sleep. While there is significant research, and new drugs on the market, to try to combat the processes that cause dementia, the disease’s resistance to currently available medications and the nearly inevitable behavioral decline that occurs still present serious challenges.

The issues with current regimens are many: Aricept and drugs like it that attempt to raise acetylcholine levels may not help very much: Newly introduced antibody medications are for mild disease, and while they may delay the development of some of the neurodegeneration that occurs, they are not without potentially serious side effects; tranquilizers can mitigate disturbing behavior but can sedate and further isolate the patient, decreasing desired interactions with family and caregivers. Many can further compromise the patient’s ability to function socially and add to a sense of isolation.

There’s increasing evidence to suggest cannabis can help. Seniors, who make up the majority of the population with dementia, are increasingly embracing cannabis, often for relief from the aches, pains, and insomnia that come with age. According to a 2022 federal survey, 8% of people 65 and older reported having used marijuana in the past year. The rate has roughly doubled in seven years, according to estimates (2). With that increase, it’s not surprising that seniors, their partners, and friends, as well as caregivers and practitioners, would notice cannabis’ positive impact on cognitive and behavioral issues in that group, patients with dementia among them.

For the last several years, I’ve been treating dementia patients with cannabis. It has been an extremely gratifying and intellectually provocative endeavor. As I’ve gotten more involved, seen more patients, and collaborated with colleagues, I’ve looked extensively at the research that’s been done. What I’ve learned is that cannabis can have a neuroprotective effect on the brain, seeming to ameliorate or mitigate degenerative, traumatic, and inflammatory processes that can occur with aging (3) as well as affect neuroplasticity (i.e., allowing new neural pathways to develop to replace those that are no longer functioning).

In addition, cannabis has many properties that can specifically target issues in dementia. There has been work done since the 1990s using various cannabinoids to control many of the symptoms of dementia: aggression, anorexia, depression, anxiety, and insomnia.

In laboratory studies in mice and clinical studies, it has been shown that cannabis can be very helpful in treating symptoms, potentially prevent deterioration and, as my colleagues both here and abroad have seen, allow patients to either decrease or discontinue entirely, their psychotropic meds. In addition, THC (the most abundant component of the plant) is at least as effective as other drugs on the market to maintain levels of acetylcholine. It also appears to prevent the development of the neurofibrillary tangles that are seen in AD. CBD (the second most abundant component) has important properties as well. It can help fight the inflammation, reactive metabolites, and cell death that goes on as any of the dementing diseases progress. (4)

But beyond all that, I have come to realize that anxiety in cognitively impaired patients drives much of their negative behavior. I recently came across a quote that continues to resonate with me and explains so much of what is happening in patients with dementia: “Memory loss erases who we are.”

Our natural response to recognition of that loss causes anxiety. All of us, if we recognized we were losing our memory, so much a bedrock of who we are, would be certain to feel anxious. Adding insult to this already deep injury, patients with dementia slowly realize they are no longer able to function independently in the world, adding to the anxiety.

CBD has a strong anxiolytic effect, so by making it the predominant cannabinoid in treatment it can significantly curb that anxiety. It can thus mitigate those unwanted behaviors without the sedation and possible psychiatric disturbances commonly used psychotropics can elicit.

An additional issue in patients with dementia is that an overwhelming proportion of them have dysfunction of the frontal lobe. This affects its role in inhibiting negative behaviors such as anxiety-exacerbated aggression, agitation, irritability, mood disturbances, and resistance to care.

Also, even in those of us who are not cognitively impaired, anxiety can prevent us from accessing information that we know is still there in our brains. CBD, with its anxiolytic effect, can prevent those blocks from occurring, and allow patients to access memories they seem to have lost. (I have had families of patients treated with cannabis tell me that their parent or loved one seems to remember more.)

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The results that I and other practitioners in the cannabis space have been seeing have been very encouraging. Whether our patients are in senior living facilities or at home, the benefits have been felt not just by the patients but by caregivers/family members as well. Patients have less pain and muscle spasticity, are less sedated, more responsive, and willing to be moved and helped by their aides In addition, they often have improved appetites and are more socially interactive, to the great pleasure of their family and caregivers.

Most exciting is a new technology, reverse engineering, looking at using salivary biomarkers that can determine which patients with dementia would (or would not) benefit from treatment with cannabis. It also can show which cannabinoids from the plant would be most helpful for them. It is a potentially game-changing process and offers great promise for patients, caregivers, pharmacists, and practitioners.

We know now that the neurologic processes predisposing patients to AD are present in the brains of patients up to 20 years before they exhibit symptoms of the disease.

I often wonder if patients with known underlying issues predisposing them to AD and other dementias should consult with a knowledgeable medical practitioner about starting a regimen of daily cannabis use early on, to prevent the development of dementia as they age.