Cannabis and Parkinson's: What are the experts recommending?
Polls predict that New Zealanders are gearing up to vote for the legalisation of marijuana in a referendum on September 19, 2020. If that is, in fact, the case, then the prominence of cannabis-related therapies is expected to rise, helped by improved availability and an anticipated rise in interest in cannabis research.
The U.S.-based Parkinson’s Foundation has released a comprehensive statement on the use of medicinal cannabis for treating Parkinson’s, which we believe may soon become relevant for people with Parkinson’s in NZ.
The report includes the findings and recommendations from more than 40 medical professionals including neurologists, nurses, pharmacists and scientists.
Urging Caution regarding Cannabis Use
According to the report, experts urge “caution” before making use of medical marijuana after a PD diagnosis.
The reason for urging caution is that there are adverse effects, toxicity issues, and drug-to-drug interactions which have not been fully understood yet for PD medications.
In surveys, people with Parkinson’s have stated benefits from using cannabis products, including reduced tremors and drop in involuntary movement or dyskinesia. Other studies have noted improvements in pain management, lowered anxiety levels and better sleep.
The report, however, points out that most cannabis and PD-related studies are not randomised, making it hard to tell if there were actual benefits to cannabis use or if they represent placebo effects and false positives.
Find out about a titan of Parkinson's research - Oleh Hornyciewicz (1926-2020)
Areas of Promise
An avenue which researchers admitted shows promise is the effect of marijuana on brain receptors called CB2, which modify inflammatory responses and are associated with the immune system.
Researchers believe there could lie the potential to protect the nervous system in Parkinson’s through cannabinoid use that targets the CB2 receptors, although there is no evidence at this time to suggest so.
Ultimately, the report is a steady reminder that there is a remarkable lack of evidence-based, scientific-backed data on the safety and efficacy of cannabis use by people with Parkinson’s (at this time).
Activating Cannabis Receptors Could Stop Involuntary Muscle Movements in Mice
A compound that affects some of the same receptors in the brain as cannabis could help reduce involuntary muscle movement — dyskinesia — that typically develops following levodopa treatment in Parkinson’s.
Treatment with Levodopa or Sinemet has long been the gold standard for Parkinson’s treatment, because of the ability to induce the chemical dopamine.
However, this medicine can lead to some nasty side-effects such as uncontrollable muscle movements through a condition called levodopa-induced dyskinesia, or LID.
Between 52-78% of all people taking levodopa medication are at risk of contracting the LID condition.
Stopping Dyskinesia through Cannabis
An Australian study, which was done on mice, used an activating agent to bind onto a cannabinoid receptor in the brain.
Cannabinoids are the active chemicals that give the cannabis plant its medicinal and recreational properties.
Numerous earlier studies have looked at the chemicals’ potential to ease motor symptoms in several neurodegenerative conditions, including Parkinson’s.
Doing so was found to reduce tremors without triggering the infamous psychoactive effects associated with cannabis.
Affecting Cannabinoid Receptors
Cannabinoid-based therapies can exert effects on glial cells which protect neurons.
The suppression of neuroinflammation and neuroprotective effects have led to cannabinoid-based therapies providing hope for mainstream application.
Cannabis itself, however, may not be suitable for the treatment of Parkinson’s symptoms as it has numerous effects which may not all be ideal for people with Parkinson’s.
The compounds in cannabis act primarily via two chemical receptors in the brain, CB1 and CB2.
While CB1 is primarily responsible for the “high” cannabis can impart, activating CB2 was shown to reduce involuntary muscle movements.
SOURCE: Neurobiology of Disease Journal, “Targeting the cannabinoid receptor CB2 in a mouse model of l-dopa induced dyskinesia”
Parkinson’s Foundation, “Parkinson’s Foundation Consensus Statement on the Use of Medical Cannabis for Parkinson’s Disease