CBD showed motor improvement in Parkinson patients but caused liver enzyme elevations
In an open-label study, high-dose CBD (Epidiolex) improved motor symptoms by 25% in Parkinson disease patients but caused elevated liver enzymes in 38.5% at the highest doses.
Quick Facts
What This Study Found
Thirteen Parkinson disease patients taking CBD at 20-25 mg/kg/day showed significant improvement in total MDS-UPDRS scores (17.8% decrease, p=0.012) and motor scores (24.7% decrease, p=0.004). Sleep and emotional/behavioral control also improved. However, elevated liver enzymes occurred in 38.5% at the highest dose, and 23% dropped out due to intolerance.
Key Numbers
13 participants (10 male); mean age 68.15; motor scores improved 24.7% (p=0.004); liver enzyme elevations in 38.5%; 3 dropouts (23%); common AEs: diarrhea (85%), somnolence (69%), fatigue (62%).
How They Did This
Open-label, dose-escalation study of 13 Parkinson disease patients titrated from 5 to 20-25 mg/kg/day pharmaceutical CBD (Epidiolex) maintained for 10-15 days.
Why This Research Matters
Cannabis use is increasingly common among Parkinson patients, but controlled data are scarce. This study provides the first dose-escalation safety and tolerability data for pharmaceutical CBD in this population.
The Bigger Picture
The motor improvement is promising but must be interpreted cautiously given the open-label design and placebo effect, which is notably strong in Parkinson disease. The liver enzyme concern suggests that the doses used in epilepsy (20-25 mg/kg/day) may be too high for this older population.
What This Study Doesn't Tell Us
Open-label design (no placebo control); very small sample; short treatment period (10-15 days); strong placebo effect known in PD trials; high dropout rate; liver enzyme concerns at therapeutic doses.
Questions This Raises
- ?Would lower CBD doses maintain motor benefits while avoiding liver issues?
- ?Will placebo-controlled trials confirm these improvements?
Trust & Context
- Key Stat:
- 24.7% motor improvement, but liver enzymes elevated in 38.5%
- Evidence Grade:
- Preliminary: very small open-label study with no placebo control; Parkinson disease has notably strong placebo effects.
- Study Age:
- Published 2020.
- Original Title:
- Safety and Tolerability of Cannabidiol in Parkinson Disease: An Open Label, Dose-Escalation Study.
- Published In:
- Cannabis and cannabinoid research, 5(4), 326-336 (2020)
- Authors:
- Leehey, Maureen A(3), Liu, Ying(4), Hart, Felecia, Epstein, Christen, Cook, Mary, Sillau, Stefan, Klawitter, Jost, Newman, Heike, Sempio, Cristina, Forman, Lisa, Seeberger, Lauren, Klepitskaya, Olga, Baud, Zachrey, Bainbridge, Jacquelyn
- Database ID:
- RTHC-02683
Evidence Hierarchy
A small preliminary study to test whether a larger study is feasible.
What do these levels mean? →Frequently Asked Questions
Does CBD help Parkinson disease symptoms?
This small open-label study showed a 25% improvement in motor scores, but without a placebo group, the true effect cannot be determined. Parkinson disease is known for strong placebo responses.
Is CBD safe for Parkinson patients?
At the high doses used (20-25 mg/kg/day), 38.5% developed elevated liver enzymes and 85% had diarrhea. Lower doses may have a better safety profile but have not been systematically studied.
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Cite This Study
https://rethinkthc.com/research/RTHC-02683APA
Leehey, Maureen A; Liu, Ying; Hart, Felecia; Epstein, Christen; Cook, Mary; Sillau, Stefan; Klawitter, Jost; Newman, Heike; Sempio, Cristina; Forman, Lisa; Seeberger, Lauren; Klepitskaya, Olga; Baud, Zachrey; Bainbridge, Jacquelyn. (2020). Safety and Tolerability of Cannabidiol in Parkinson Disease: An Open Label, Dose-Escalation Study.. Cannabis and cannabinoid research, 5(4), 326-336. https://doi.org/10.1089/can.2019.0068
MLA
Leehey, Maureen A, et al. "Safety and Tolerability of Cannabidiol in Parkinson Disease: An Open Label, Dose-Escalation Study.." Cannabis and cannabinoid research, 2020. https://doi.org/10.1089/can.2019.0068
RethinkTHC
RethinkTHC Research Database. "Safety and Tolerability of Cannabidiol in Parkinson Disease:..." RTHC-02683. Retrieved from https://rethinkthc.com/research/leehey-2020-safety-and-tolerability-of
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.