Does Marijuana Use Predispose People to Parkinson's Disease?
No, there is no evidence that marijuana use predisposes individuals to developing Parkinson's disease. The available medical literature does not establish any causal relationship between cannabis consumption and increased risk of Parkinson's disease development.
What the Evidence Actually Shows
No Link Between Cannabis and Parkinson's Risk
The current body of evidence, including recent systematic reviews and clinical studies, does not identify cannabis use as a risk factor for Parkinson's disease 1, 2, 3. Research has instead focused on whether cannabis might treat Parkinson's symptoms rather than cause the disease 1, 2.
Cannabis as Potential Treatment (Not Cause)
- Studies have investigated whether cannabinoids like CBD and THC might offer therapeutic benefits for existing Parkinson's disease, examining effects on motor symptoms (tremor, bradykinesia) and non-motor symptoms (pain, anxiety, sleep) 2, 4, 3.
- A 2023 systematic review found cannabinoids capable of improving motor symptoms more than placebo, with CBD improving psychiatric symptoms in a dose-dependent manner 2.
- Real-world survey data from 1,881 people with Parkinson's showed subjective improvements in pain, anxiety, and sleep with cannabis use, though this does not establish causation or prevention 5.
Important Caveats About Cannabis Use
Well-Documented Risks That Do Exist
While cannabis does not cause Parkinson's disease, it carries significant health risks that warrant consideration:
Neurological and Psychiatric Risks:
- Cannabis use may exacerbate psychiatric disorders in vulnerable individuals and increase risk for developing depressive disorders 6, 7.
- High doses of THC are associated with psychotic symptoms 6.
- Early onset cannabis use strongly predicts future dependence and neuropsychological decline 6.
Cardiovascular Risks:
- Cannabis is associated with adverse cardiovascular events including myocardial infarction, stroke, arrhythmias, and orthostatic hypotension 8, 6, 7.
- In older adults, acute cannabis toxicity may be associated with sedation, obtundation, and myocardial ischemia 9, 6.
Substance Use Disorder:
- Approximately 10% of adults with chronic cannabis use develop cannabis use disorder 9, 6, 7.
- Long-term daily users may experience withdrawal symptoms including irritability, insomnia, sleep disturbances, and appetite changes lasting up to 14 days 9, 6.
Other Physical Risks:
- Long-standing cannabis use can lead to cannabinoid hyperemesis syndrome, characterized by cyclical vomiting relieved by hot showers 9, 6.
- Cannabis smoking affects lung function and is associated with chronic bronchitis and chronic obstructive pulmonary disease 9, 6.
- Cannabis users are more than twice as likely to be involved in motor vehicle crashes 9, 7.
Special Population Concerns
Older Adults:
- Cannabis-related emergency department visits among older adults have increased 9, 6.
- Older adults who use cannabis may be at higher risk for behavioral health issues including anxiety and depression 9, 6.
Pregnant Individuals:
Clinical Bottom Line
Cannabis does not cause Parkinson's disease. However, if someone with Parkinson's disease is considering cannabis for symptom management, they should understand that while some patients report subjective benefits for pain, anxiety, and sleep, the evidence remains insufficient to make definitive recommendations 1, 3. The well-documented risks—particularly cardiovascular events, psychiatric exacerbation, substance use disorder, and cognitive effects—must be weighed against uncertain therapeutic benefits 6, 7.
Healthcare providers should engage in open, non-judgmental conversations about cannabis use with patients, ensuring they understand both the lack of evidence for disease causation and the documented health risks associated with use 8, 7.