Parkinson’s Disease and Marijuana
With approximately a million individuals living with Parkinson’s and 60,000 people being diagnosed with Parkinson’s Disease annually in the US it is a big problem causing problems for the patients, their caretakers and loved ones. It is a disease more common in the elderly and with an aging population worldwide this is becoming a relatively common disease affecting about 1% of those above the age of 60. .
Cannabis is increasingly being considered therapeutically as it is currently legalized in 33 states and Washington, DC, with more states making access to cannabis legal every election cycle. The possibility of Federal legalization has also increased with time and acceptance of the population and the Biden administration has made legalization and research top priorities.
The Science Behind Marijuana and Parkinson’s
The Science of Cannabis receptors
Cannabis is effective because the plant derived cannabinoids (phytocannabinoids) have a similar structure to endogenous cannabinoids (created naturally within the body – e.g. anandamide). In the same was as opioids work by their interaction with naturally occurring opioid receptors, cannabinoids interact with CB1 and CB2 receptors which are found in the brain and brain/periphery respectively. Receptors are molecular switches which sit on the outside surface of cells and when they interact with certain other molecules (or families of molecules) and upon activation effect the pathways internally within the cell.
In the brain the CB1 receptors effect changes in nerve cells (neurons) effective brain function such as thinking, feeling, pain perception and many body functions. These receptors were discovered in the 1990’s and make up the endocannabinoid system which is found in all vertebrates and is a very very old system within animals.
It started with anecdotal reports
While scientist have considered cannabinoids as being neuroprotective (limiting the damage to nerve cells), and there have been reports of marijuana helping relieve the tremor symptoms of Parkinson’s, it was perhaps the internet that really allowed these stories to surface through their spread on social media.
There was also evidence supported by animal models that looked at THCV with its anti-oxidant properties and its potential for the protection of neurons and alleviation of symptoms. They concluded that “THCV has a promising pharmacological profile for delaying disease progression in PD and also for ameliorating parkinsonian symptoms.”
Studies and Trials
Cannabinoids have been studied in other symptoms of PD including:
- bradykinesia (slowness of movements)
- dyskinesia (excess movement caused by levodopa)
Currently the scientific consensus is that there is not any meaningful or conclusive benefits of marijuana in patients with Parkinson’s Disease.
Additionally Parkinson’s Disease itself can affect thinking by impairing executive function. This affects the patients ability for planning and limiting risky behaviors. As such the psychoactive effects of THC can potentially further affect the brain function. (Read below in Risks vs Benefits)
Unfortunately there have been due to the illegality of cannabis for the past 80 years – very little adequate research in cannabis and Parkinson’s disease. Of the clinical trials conducted – none were the gold standard – that is of a double blind, placebo controlled design and the number of participants very small.
Since the election of President Biden in 2020 there has been a focus on more clinical research in cannabis and cannabinoids in areas such as cancer and opioids.
Risks vs Benefits of Cannabis in Parkinson’s
Risks of THC usage in patients with Parkinson’s disease have several risks to consider such as THC induced:
- impaired cognition
- blurred vision
- balance issues
At the same time – some patients may benefit from possible benefits such as improved:
- pain management
You should consult with your physician if you are considering using cannabis.