Patient question · asked by Anonymous reader · September 17, 2026
Does cannabis help with tremor in Parkinson's disease?
My father has Parkinson's and keeps reading that cannabis helps with tremor. Is there anything behind that?
Patient question: My father has Parkinson's and keeps reading that cannabis helps with tremor. Is there anything behind that? For now, less than the enthusiasm suggests. In a randomised trial of a high-CBD, low-THC extract, motor scores improved in both the treatment and placebo groups, and the difference between them was not statistically significant.
Dr. Caplan & CED Research Response
For now, less than the enthusiasm suggests. In a randomised trial of a high-CBD, low-THC extract, motor scores improved in both the treatment and placebo groups, and the difference between them was not statistically significant. Sleep, thinking and daily activities slightly favored placebo. There are many other reviews that tell different stories, and the general public clamor around it suggests that Science still has much to learn.
What makes this trial instructive is the strong placebo response. Motor scores did improve on the extract - by 4.57 points on the MDS-UPDRS - and if you only looked at that number you would conclude it worked. But placebo improved by 2.77, and the between-group difference of 1.80 points was not significant. People genuinely felt and measured better on both.
That pattern is common in Parkinson's research and is one reason personal accounts, however sincere, are hard to reason from.
The honest limits: the trial ran two weeks, which is short for a progressive condition, and enrolled 61 people. The authors are explicit that this does not close the question and that longer trials are needed. It does mean there is not yet good evidence for the benefit many families are hoping for.
The study behind this answer
Short-Term Cannabidiol with Δ-9-Tetrahydrocannabinol in Parkinson’s Disease: A Randomized Trial (Movement Disorders, 2024) · PubMed 38487964
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Reviewed by Dr. Caplan on September 17, 2026.
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