Research study · Movement Disorders · 2024
Short-Term Cannabidiol with Δ-9-Tetrahydrocannabinol in Parkinson’s Disease: A Randomized Trial
A 2024 randomized controlled trial in Movement Disorders tested cannabidiol in Parkinson's disease. Motor scores improved in both groups, and the difference between them was not significant. Parkinson's is one of the conditions people ask about most, and this trial did not find the benefit many hope for.
Study overview
A short randomised trial of a high-CBD, low-THC oral extract in 61 people with Parkinson's disease, a group who use cannabis often despite thin evidence.
Findings
Motor scores improved in both groups, and the difference between them was not significant. Sleep, thinking and daily activities slightly favoured placebo, and mild side effects were more common on the extract.
Why this matters
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.
Abstract
Participants with Parkinson's disease scoring at least 20 on the motor MDS-UPDRS, and who tested negative for cannabis at baseline, took an oral sesame oil cannabis extract for two weeks, escalating to 2.5 mg/kg/day. Thirty-one were randomised to CBD/THC and 30 to placebo. The mean final dose was 191.8 mg CBD and 6.4 mg THC daily.
Motor MDS-UPDRS fell by 4.57 points (95% CI, -8.11 to -1.03; P = 0.013) on CBD/THC and by 2.77 (-4.92 to -0.61; P = 0.014) on placebo. The between-group difference - the number that matters - was -1.80 (-5.88 to 2.27; P = 0.379), which is not significant. Several assessments showed a strong placebo response.
Sleep, cognition and activities of daily living showed a treatment effect favouring placebo. Overall adverse events were mild but more frequent on the extract. Plasma levels at the final dose were 54.0 ng/mL CBD and 1.06 ng/mL THC. The authors are direct that a two-week duration and a strong placebo response limit what can be concluded, and call for longer trials.
Citation
Liu Y, Bainbridge J, Sillau S, Rajkovic S, Adkins M, Domen CH, et al. Short-Term Cannabidiol with Δ-9-Tetrahydrocannabinol in Parkinson’s Disease: A Randomized Trial. Movement Disorders (2024). PubMed 38487964 · DOI
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Condition: Parkinson's disease Topic: CBD Topic: THC
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Reviewed by Dr. Caplan on September 17, 2026.
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