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.
The short answer
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.
A closer lookWhy the answer is what it is
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 evidence
The study behind this answer
Verified on PubMed Randomized controlled trial
Short-Term Cannabidiol with Δ-9-Tetrahydrocannabinol in Parkinson’s Disease: A Randomized Trial
PubMed 38487964
Read the abstract as published
BACKGROUND: Cannabis use is frequent in Parkinson's disease (PD), despite inadequate evidence of benefits and risks.
OBJECTIVE: The aim is to study short-term efficacy and tolerability of relatively high cannabidiol (CBD)/low Δ-9-tetrahydrocannabinol (THC) to provide preliminary data for a longer trial.
METHODS: Persons with PD with ≥20 on motor Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) who had negative cannabis testing took cannabis extract (National Institute of Drug Abuse) oral sesame oil solution for 2 weeks, increasing to final dose of 2.5 mg/kg/day. Primary outcome was change in motor MDS-UPDRS from baseline to final dose.
RESULTS: Participants were randomized to CBD/THC (n = 31) or placebo (n = 30). Mean final dose (CBD/THC group) was 191.8 ± 48.9 mg CBD and 6.4 ± 1.6 mg THC daily. Motor MDS-UPDRS was reduced by 4.57 (95% CI, -8.11 to -1.03; P = 0.013) in CBD/THC group, and 2.77 (-4.92 to -0.61; P = 0.014) in placebo; the difference between groups was non-significant: -1.80 (-5.88 to 2.27; P = 0.379). Several assessments had a strong placebo response. Sleep, cognition, and activities of daily living showed a treatment effect, favoring placebo. Overall adverse events were mild and reported more in CBD/THC than placebo group. On 2.5 mg/kg/day CBD plasma level was 54.0 ± 33.8 ng/mL; THC 1.06 ± 0.91 ng/mL.
CONCLUSIONS: The brief duration and strong placebo response limits interpretation of effects, but there was no benefit, perhaps worsened cognition and sleep, and there was many mild adverse events. Longer duration high quality trials that monitor cannabinoid concentrations are essential and would require improved availability of research cannabinoid products in the United States. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Abstract text as indexed by PubMed for this identifier.
In practice
What this study does and does not change
Parkinson's is one of the conditions people ask about most, and this trial did not find the benefit many hope for. Two weeks is short, so it settles less than it seems - but it is the evidence we have.
A physician's read of the cited study, as it appears on that study's page.
Back to Daily Research and Patient Questions
Reviewed by Dr. Caplan on September 17, 2026.
This answer is general education. It is not medical advice and does not create a doctor-patient relationship. For care specific to you, book a consultation. In an emergency, call 911.
