Cannabis use in people with Parkinson’s disease: Reported patterns of use, symptomatic benefits, and adverse effects via Fox Insight
Samantha Holden1, Christopher Domen2, Stefan Sillau1, Ying Liu1, Maureen Leehey1
1Neurology, 2Neurosurgery, University of Colorado School of Medicine
Investigate the frequency and magnitude of symptomatic effects reported with cannabis use in Parkinson’s disease (PD).
People with PD may consider using cannabis for therapeutic purposes, but there is limited evidence on efficacy and dosing, including quantities of tetrahydrocannabinols (THC) and cannabidiols (CBD). Thus, many people with PD are taking cannabis without medical guidance. Valuable information can be gained by asking about subjective experiences with cannabis in PD. 
An anonymous, 15-question, web-based survey was hosted by the Michael J. Fox Foundation Fox Insight platform. The introduction defined cannabis product types and asked respondents to reference their product labels. Questions focused on use patterns and subjective effects on thirty-six predefined symptoms (rated from -2-markedly worse to +2-markedly better).
1,881 people with PD with cannabis use experience responded (58.5% men; mean age 66.5 years; 50.5% <3 years of PD). 73.0% reported medicinal purpose of cannabis use, though 30.8% of all respondents did not inform their doctor. 86.7% knew the type of cannabis product they took: 69.8% took higher CBD products and 30.2% higher THC. Most common use was via oral administration, once daily, and for less than six months duration. Frequent improvements were reported for sleep, anxiety, agitation, and pain (>50% of respondents, mean magnitude 0.69-0.89). Dry mouth, dizziness, and cognitive changes were common adverse effects (20.9-30.8% of respondents, mean magnitude -1.16 to -1.21). More frequent symptomatic changes of greater magnitude, both beneficial and adverse, were reported with higher THC products.

People with PD are using more CBD products, via oral administration, with mild subjective benefits in sleep, pain, and mood symptoms. Adverse effects were relatively less frequent, though of greater magnitude. Higher THC products may be higher risk/higher reward for symptomatic effects in PD. This information may allow clinicians to better counsel patients and provide a foundation for future studies.