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Clinical Trial
. 2023 Jul;38(7):1341-1346.
doi: 10.1002/mds.29447. Epub 2023 May 22.

Cognitive Safety Data from a Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Phase IIb Study of the Effects of a Cannabidiol and Δ9-Tetrahydrocannabinol Drug on Parkinson's Disease-Related Motor Symptoms

Christopher H Domen  1 , Stefan Sillau  2 , Ying Liu  2 , Michelle Adkins  3 , Sarah Rajkovic  4 , Jacquelyn Bainbridge  3 , Cristina Sempio  5 , Jost Klawitter  5 , Maureen A Leehey  2
Affiliations
Clinical Trial

Cognitive Safety Data from a Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Phase IIb Study of the Effects of a Cannabidiol and Δ9-Tetrahydrocannabinol Drug on Parkinson's Disease-Related Motor Symptoms

Christopher H Domen et al. Mov Disord. 2023 Jul.

Abstract

Background: Cannabis is increasingly available worldwide but its impact on cognition in Parkinson's disease (PD) is unknown.

Objective: Present cognitive safety data from study of an oral high-dose cannabidiol (CBD; 100 mg) and low-dose Δ9-tetrahydocannabinol (THC; 3.3 mg) drug in PD.

Methods: Randomized, double-blind, parallel-group, placebo-controlled study of a CBD/THC drug administered for 16.3 (SD: 4.2) days, with dosage escalating to twice per day. Neuropsychological tests were administered at baseline and 1-1½ hours after final dose; scores were analyzed with longitudinal regression models (alpha = 0.05). Cognitive adverse events were collected.

Results: When adjusted for age and education, the CBD/THC group (n = 29) performed worse than the placebo group (n = 29) on Animal Verbal Fluency. Adverse cognitive events were reported at least twice as often by the CBD/THC than the placebo group.

Conclusion: Data suggest this CBD/THC drug has a small detrimental effect on cognition following acute/short-term use in PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Keywords: Parkinson's disease; cannabidiol; cannabis; cognition; Δ9-tetrahydrocannabinol.

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