In the spring of 2019, the Parkinson’s Foundation held its first ever medical conference to discuss the viability of cannabis and cannabis-based treatments to help control symptoms of this tragic neurodegenerative disorder.
Parkinson’s patients all over the country overwhelmingly use marijuana medicinally — 80 percent, according to one survey — but the research on whether it really helps calm the motor symptoms of the disease is scant and inconclusive.
“The Parkinson’s Foundation is bringing together experts from across the globe to discuss the implications and recommendations of medical marijuana use for people with Parkinson’s,” said James Beck, PhD, chief scientific officer of the Parkinson’s Foundation, in a press release. “Now that medical marijuana is legal in 33 states and in many other countries, people are equating access to efficacy. It is imperative that we address the clinical implications of medical marijuana use among people with PD.”
The conference was closed to the public, but it’s very existence makes clear the pharmaceutical industry and medical community are starting to take cannabis seriously as a source for Parkinson’s remedies.
What is Parkinson’s disease?
Parkinson’s disease is the 14th leading cause of death in the U.S., according to the Parkinson’s Foundation. Interestingly, people do not die directly from Parkinson’s, but from complications relating to the tremor, walking and balance issues and other neurological symptoms that become worse over time. For example, your brain’s control of swallowing may deteriorate in later stages, making it difficult to eat and causing food to get into your lungs, leading to fatal pneumonia.
In Parkinson’s, the neurons in the brain that make dopamine start to die, according to the National Institute on Aging. Dopamine is a critical signaling chemical that allows you to control your limbs and skeletal muscles. As dopamine production deteriorates, tremors and muscle problems become worse.
Parkinson’s also blights the nerve endings that produce norepinephrine, a critical neurotransmitter that helps control the function of autonomic processes like blood circulation and the waves of muscle contractions that move food through your gastrointestinal tract, leading to difficulty swallowing and swings in blood pressure, according to the NIA.
Some Parkinson’s patients also develop dementia caused by the proliferation of abnormal protein clumps in the brain called Lewy bodies.
Does marijuana treat parkinson’s symptoms?
Right now, it seems fairly clear that cannabidiol (CBD), the non-psychoactive cannabinoid in marijuana, and other cannabinoids help Parkinson’s patients reduce the anxiety, insomnia, muscle stiffness and loss of appetite that often accompanies the disease.
But figuring out whether it eases the motor symptoms that make Parkinson’s so debilitating is much trickier. Patients report anecdotally some relief from consuming whole marijuana. Furthermore, the weed components, cannabidiol (CBD) and Delta-9 Tetrahydrocannabinol (THC), protect brain cells in rodents treated with toxins that kill brain cells to mimic Parkinson’s. CBD-treated rodents never developed Parkinson’s symptoms, even when researchers injected poison directly into their brains to kill the dopamine-producing cells that tend to degenerate over the disease’s progression.
The few Parkinson’s/cannabis studies conducted on humans haven’t shown that marijuana in general or the non-psychoactive component CBD helps with the tremors and seizure-like fainting episodes that come with later stages of the disease. These studies are weak, however, because they are based on self-reporting. There are all sorts of ways the data can warp based on people’s faulty memories, ignorance of strain and potency for their cannabis product of choice, and the assumption that people with positive experiences with medical pot are more likely to fill out the survey.
More damning, however, is the fact none of the few study populations used more than 50 volunteers — often fewer than 20.
Dr. Benzi M. Kluger, a professor of psychiatry and neurology at the University of Colorado Denver, said these results might as well read as inconclusive. In a webinar hosted by the Parkinson’s Foundation, he stressed the need for robust clinical trials to hash out exactly how administering cannabinoids could help Parkinson’s patients’ motor symptoms.
Randomized controlled trials have been inconclusive also because they use single-dose, single-formulation cannabinoid preparations.
“We may have been using the wrong cannabis product, or the wrong dosage,” Kluger said.
Furthermore, cannabis seems more effective in many instances — not just for Parkinson’s treatment, but in general — when it’s consumed in whole form, or as a combination of some ratio of CBD and THC. This is called the entourage effect, meaning the hundreds of cannabinoids and terpenes in the whole plant interact to temper the effects of any single chemical in the plant when consumed.
One interesting fact of the rodent studies: CBD seems to have an anti-inflammatory protective effect on brain cells, independent of its interaction with the body’s endocannabinoid system, the nerve signaling system made up of the body’s naturally produced cannabinoids and the receptors on nerve cell membranes into which they lock to send messages.
Researchers in other cannabis studies have also noted this effect, and it could be a clue that CBD does way more in the body than just lock into the endocannabinoid system. This could even be a clue to some as yet undiscovered component of the endocannabinoid system.
What are the next steps in researching CBD and cannabis for Parkinson’s?
In the pharmaceutical industry, randomized controlled trials are the gold standard for determining whether a particular substance has any effect. Some of the volunteers get a placebo while others get a standardized dose of CBD or whatever cannabis formulation scientists are testing. The results in the medicated population have to be significantly better than the placebo group to show the medication is effective.
Currently, a Canadian study is underway to look at the effectiveness of cannabis oil on Parkinson’s patients. It’s sponsored by the University Health Network, Toronto and the Parkinson’s Society of Canada. The study will conclude in July of 2019, according to ClinicalTrials.gov.