Cannabidiol and Tetrahydrocannabinol Use in Parkinson’s Disease: An Observational Pilot Study

Background: There is a need for more research examining the use of cannabis, tetrahydrocannabinol (THC), and cannabidiol (CBD) products in people with Parkinson’s disease (PD), especially given the recent increase in the use of these products. Objectives: Given the recent increase in over-the-counter CBD use as well as the prescription of medical cannabis by treating physicians, the utilization method, effects on motor and non-motor symptoms, side effects, and attitude toward cannabis use were examined in a naturalistic sample of patients with PD. Methods: A total of 15 individuals with PD, eight of whom were prescribed CBD/THC treatment and seven who were not taking any CBD/THC product, were assessed cross-sectionally. Participants completed structured neuropsychological testing, motor assessment, and questionnaires regarding mood, subjective cognition, and symptom levels. T-tests were completed for quantitative measures and descriptive data were examined and described. Due to the small sample size, Shapiro-Wilk tests for normality were utilized and Mann-Whitney U analyses were completed when appropriate. Results: We found a wide range of prescribed products and methods as well as variability in perceived benefits and untoward effects, even in our small sample. Individuals with PD who were taking a CBD/THC product had lower global cognition scores on the Montreal Cognitive Assessment (MoCA) but no detectable differences among more specific neuropsychological measures. They also had more non-motor symptoms of PD but no differences in motor symptom levels. Qualitatively, some participants with PD who were taking CBD/THC reported improved pain levels, sleep, and reductions in anxiety. A few negative effects were endorsed, including sleepiness, concentration difficulties, and forgetfulness. Conclusion: CBD/THC utilization in PD is varied. In our small sample, individuals who utilized the treatment had lower MoCA scores, more non-motor symptoms, and descriptively reported improvements in sleep, anxiety, and pain, and had side effects of sleepiness and cognitive difficulty. Future studies should focus on clinical trials with standardized CBD/THC methods of use.