Can Cannabis Treat Or Even Prevent Dementia?

Use of certain strains of medical cannabis has been demonstrated anecdotally and scientifically to alleviate various symptoms of aging, including symptoms prominent for a loved one with sundowners. It is effective in treating insomnia, and calming down anxiety. It also has strong effects of calming down problematic behaviors, including panic driven flight responses or violence.

While symptoms of dementia can vary greatly, at least two of the following core mental functions must be significantly impaired to be considered dementia:

  • Memory
  • Communication and language
  • Ability to focus and pay attention
  • Reasoning and judgment
  • Visual perception

People with dementia may have problems with short-term memory, keeping track of a purse or wallet, paying bills, planning and preparing meals and remembering appointments.

Can cannabis prevent or treat dementia?

There have been a number of articles in newspapers and blogs over the years that claim that cannabis or one of its components could help to prevent or treat dementia, particularly Alzheimer’s disease.
The hippocampus, which contains the CB1 receptor, is known to be vulnerable to the underlying causes of Alzheimer’s disease and this damage contributes towards the problems with memory and learning associated with the disease. There is also building evidence that the microglia, which contain the CB2 receptor, play a crucial role in the development of Alzheimer’s disease. Coupled with this, some studies have found that people with Alzheimer’s disease have an increased number of CB2 receptors in their brains.

There has been some research interest in the role of the endocannabinoid system as a potential target for treatments for Alzheimer’s disease. A small open-label trial conducted by Israeli researchers found that THC helps relieve symptoms of dementia in patients with Alzheimer’s disease. Findings in a new study published in The Journal of Alzheimer’s Disease suggest that cannabis extracts containing tetrahydrocannabinol (THC) are beneficial at relieving symptoms in patients with Alzheimer’s disease. The researchers also recorded a significant reduction in behavioral and psychological symptoms of dementia, including agitation, aggression, irritability, apathy, delusions, and sleep. Those who care for a person with Alzheimer’s disease commonly are affected by physical and emotional burdens, but the study found that giving patients cannabis oil with THC also significantly reduced caregiver stress.

However, as yet no studies or trials have looked into the effects of cannabis or its components on the underlying causes of Alzheimer’s disease in people. Whilst the studies in the laboratory show some promise, we need to understand the wider effects that these components have before we can know whether they have any effect – positive or negative – on the development of Alzheimer’s in people.

It is also worth noting that many of these studies have involved a particular component of cannabis in isolation. Even if one component is found to influence dementia risk, it doesn’t necessarily mean that taking cannabis would have the same effect. There is also a large amount of variation in the levels of THC and CBD in different strains of the plant so the effects could depend on the type of cannabis used.

Can cannabis treat some of the symptoms of dementia?

Cannabis contains various compounds known as cannabinoids, which are structurally similar and have varying effects on brain function and metabolism. Of these, arguably the most important are THC and CBD, which have a range of physiological effects relevant to dementia—they can reduce inflammation, act as antioxidants and neuroprotectants, and even stimulate the growth of new neural tissue.

Inflammation of neural tissue is increasingly thought to play a major role in the development of dementia. It is thought that acute inflammation that initially occurs as a defense mechanism may lead to an uncontrolled chain reaction resulting in chronic inflammation and neuronal deterioration. CBD is non psychoactive, have anti-inflammatory, anti-anxiety, neuro protective and pain killing properties, making it an ideal option to treat dementia.

Oxidative stress and the release of reactive oxygen species is a key component of diseases such as Dementia, and is inherently associated with immune inflammation—when inflammation occurs, it induces oxidative stress, reduces the antioxidant capacity of cells, and causes the production of free radicals such as reactive oxygen species, which in turn react with fatty acids and proteins in the cell membranes. In 2004, a study demonstrated that exposing cells to amyloid beta caused a significant decline in cell survival, but that treating the cells with cannabidiolprior to amyloid beta exposure caused a notable increase in cell survival. Medical cannabis seems to destroy the poisonous protein amyloid beta – which has been linked to memory loss.

Cannabidiol is also thought to promote the growth of new neural tissue (a process known as neurogenesis). In Dementia, the rapid destruction of neural tissue causes devastating neurological effects, and the normal processes of neurogenesis are interrupted by the presence of amyloid beta. Developing therapies that can stimulate neurogenesis may therefore slow the progression of the disease or even reverse its symptoms to some extent.

The few clinical trials that have taken place on the effects of cannabis for people affected by dementia have looked at whether the drug can help to manage some symptoms of the condition. Symptoms such as agitation and aggression could in theory be counteracted by the effects of cannabis or its components.

A few small clinical trials have assessed the effects of cannabinoids, including THC and synthetic cannabinoids such as nabilone, on behavioural symptoms of dementia. However, scientific reviews have found that the trials and studies so far have generally been small or of low quality (see here and here for references), making it difficult to come to an informed conclusion.

This trial’s findings are just the latest in a growing body of evidence suggesting cannabis’ efficacy for Alzheimer’s disease. Previous studies have found THC to be effective at lowering levels of amyloid-beta peptide, the hallmark characteristic and key contributor to the progression of Alzheimer’s disease. Long-term inflammation encourages the progression of Alzheimer’s disease, but cannabinoids have also shown to provide neuroprotective effects by helping stimulate the removal of amyloid-beta and blocking the inflammatory response.