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

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

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.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cannabidiol* / adverse effects
  • Cannabis*
  • Cognition* / drug effects
  • Double-Blind Method
  • Dronabinol / adverse effects
  • Humans
  • Parkinson Disease* / drug therapy

Substances

  • Cannabidiol
  • Dronabinol