Medical cannabis has been touted as an effective treatment for a variety of conditions: glaucoma, epilepsy, multiple sclerosis, and even cancer. But is this controversial product also a potentially treatment for people with Parkinson’s disease? Potentially. According to Parkinson’s News Today, however, the verdict is still pretty unclear without additional research.

Parkinson’s Disease

Parkinson’s disease is a progressive central nervous system disorder which occurs in five distinct stages. In the first stage, many patients only experience light symptoms, like a tremor. However, by the time they progress to stage five, most patients no longer have control over their movement. There is no specific cause of Parkinson’s disease. But some hypothesize that it results from genetics, toxins, or Lewy bodies. It occurs when brain neurons degenerate and die, causing a loss of dopamine production. Since dopamine helps the body and brain communicate, people with Parkinson’s slowly lose control of their muscles. Most patients are over 50.

Symptoms of Parkinson’s disease include rigid and stiff muscles, slowed movement, changes in balance and posture, the development of speech changes like stuttering, hallucinations, tremors, and rubbing the thumb and index finger together. Learn more about Parkinson’s.

Medical Cannabis

Medical cannabis is still extremely controversial, in part because cannabis is not nationally legalized yet. Currently, marijuana legalization is as followed:

• Fully illegal: 8 states
• Decriminalized: 3 states
• Medical Cannabis: 16 states
• Medical & Decriminalized: 12 states
• Fully Legal (Recreational and Medical): 11 states and Washington, D.C.
• Medically Legal for Parkinson’s: 17 states

According to Harvard Medical School, approximately 7 million Americans use medical cannabis. Additionally, around 85% of Americans support medical cannabis legalization. The school also notes that there are different “subsets” of medical cannabis, used for different purposes:

• CBD. CBD, or cannabidiol, is derived from the hemp plant. Unlike THC, CBD does not get someone “high.” As a result, CBD products are more widely available in the United States. CBD is known to help relieve pain, help with insomnia, and even effectively treat children with Dravet syndrome. Learn more about CBD.
• THC. THC, or tetrahydrocannabinol, is what causes people to feel “high” when smoking cannabis. It attaches to cannabinoid receptors in the brain to impact memory, pleasure, thinking, coordination, and perception. Learn more about THC.

Patients using medical cannabis can smoke the kind that only gives them THC. Medical cannabis is often used for pain management. Admittedly, this is not effective for severe pain caused by surgery or injury, but it is effective for chronic pain.

Medical cannabis is a burgeoning choice for pain management as it is less addictive, and thus safer, than opiates. It is also relaxing without sedative effects. The FDA approved Epidiolex and dronabinol, which both contain either THC or CBD, for the treatment of epilepsy, cancer, and AIDS.

Parkinson’s disease & Medical Cannabis

So many people believe that medical cannabis is effective in treating pain, muscle tremors, nausea, and other symptoms of various conditions. However, the Parkinson’s Foundation is still unsure of its efficacy in treating patients with Parkinson’s.

The Foundation created a consensus statement, based on the opinions of 40 medical experts including patients with Parkinson’s disease, clinicians, researchers, nurses, pharmacologists, and industry and non-profit members. Together, they advocated for patients to:

• Use caution when using medical cannabis. Only smoke or use cannabis products at home. Additionally, be aware of how certain products act. THC hits quicker when smoking. However, smoking can impact lung health. Edibles can take up to 1-2 hours to kick in, but last longer. People using edibles should be careful of doses and avoid taking more before the initial feeling kicks in to prevent toxicity.
• Communicate with your doctors. Patients using medical cannabis should openly communicate with their doctors about symptoms (or symptom reduction), adverse reactions, and dosages.
• Start at lower doses of THC. Micro-doses of THC start at 2mg, but some products (like edibles) can go up to 10-20mg. Patients, whether smoking or taking edibles, should start on low doses to understand how medical cannabis affects them.
• Monitor for potential side effects. Despite its benefits, cannabis can have negative side effects. Patients should speak to their doctor if they experience:
  • Severe fatigue
  • Dizziness
  • Cognitive impairment
  • Paranoia or hallucinations
  • Nausea and vomiting
  • Gastrointestinal issues
  • Anxiety or depression
  • Issues with memory
• Be aware of potential drug interactions. Enzymes in your liver break down cannabinoids. These same enzymes can process and break down certain medications, causing a potential drug interaction or reducing treatment efficacy. Patients should speak to their doctors about any medications.

Study Limitations

Unfortunately, the relationship between Parkinson’s disease and medical cannabis is relatively unclear. This is because there has been a lack of research on the subject. In fact, only four clinical trials tested the relationship between Parkinson’s disease and medical cannabis. According to the Parkinson’s Foundation:

“These trials have uniformly failed to find evidence of benefit. However, the lack of consistency in the ways these studies were conducted, the ways in which cannabis was given, and the way outcomes were measured, make these studies inconclusive at best.”

Additionally, many of these trials had small sample sizes and few placebos. The largest trial only had 24 patient participants. None of the four trials had patients smoking medical cannabis.

Next, open-label studies highlight benefits from reduced pain, reduced tremors, and better sleep. However, the Parkinson’s Foundation notes that all patients knew they were using medical cannabis so they could have expected their results.

Finally, no studies have looked to research the best types of cannabinoids, or the best dosage, for patients with Parkinson’s disease.

Moving Forward

To determine the efficacy of medical cannabis for patients with Parkinson’s, additional research is needed. In the interim, the Parkinson’s Foundation tells people to use cannabis at their own risk. When purchasing medical marijuana, they also state to use a single dispensary so that patients get acclimated to one product.