“Background: Whole-plant medical cannabis (MC) products are widely used for controlling symptoms associated with Parkinson’s disease (PD). Despite its widespread use, few studies have investigated the long-term impact of MC on the progression of PD or its safety profile. This study examined the effects of MC on PD in a real-life setting.

Methods: A retrospective case-control study of 152 idiopathic PD patients (mean age 69.1 ± 9.0 years), followed at the Sheba Medical Center Movement Disorders Institute (SMDI) from 2008 to 2022 was conducted. Seventy-six patients who used licensed whole-plant medical cannabis (MC) for at least a year were compared to a matched group who did not receive MC in terms of their Levodopa Equivalent Daily Dose (LEDD), Hoehn and Yahr (H&Y) stage, and cognitive, depressive, and psychotic symptoms.

Results: The median monthly dose of MC was 20 g (IQR: 20-30), with a median Tetrahydrocannabinol (THC) percentage of 10 (IQR: 9.5-14.15) and a median Cannabidiol (CBD) percentage of 4 (IQR: 2-10). There were no significant differences between the MC and the control groups for LEDD or H&Y stage progression (p = 0.90, 0.77, respectively). A Kaplan-Meier analysis showed no evidence of relative worsening of psychotic, depressive, or cognitive symptoms reported by patients to their treating physicians over time in the MC group (p = 0.16-0.50).

Conclusion: Over the 1-3 years of follow-ups, the MC treatment regimens appeared to be safe. MC did not exacerbate neuropsychiatric symptoms and had no detrimental effects on disease progression.”

https://pubmed.ncbi.nlm.nih.gov/37211456/

https://www.prd-journal.com/article/S1353-8020(23)00129-3/fulltext

“Objectives: Medical cannabis (MC) has recently garnered interest as a potential treatment for neurologic diseases, including Parkinson’s disease (PD). A retrospective chart review was conducted to explore the impact of MC on the symptomatic treatment of patients with PD.

Methods: Patients with PD treated with MC in the normal course of clinical practice were included (n = 69). Data collected from patient charts included MC ratio/formulation changes, PD symptom changes after initiation of MC, and adverse events (AEs) from MC use. Information regarding changes in concomitant medications after MC initiation, including opioids, benzodiazepines, muscle relaxants, and PD medications, was also collected.

Results: Most patients were initially certified for a 1:1 (∆ 9 -tetrahydrocannabinol:cannabidiol) tincture. Eight-seven percent of patients (n = 60) were noted to exhibit an improvement in any PD symptom after starting MC. Symptoms with the highest incidence of improvement included cramping/dystonia, pain, spasticity, lack of appetite, dyskinesia, and tremor. After starting MC, 56% of opioid users (n = 14) were able to decrease or discontinue opioid use with an average daily morphine milligram equivalent change from 31 at baseline to 22 at the last follow-up visit. The MC was well-tolerated with no severe AEs reported and low rate of MC discontinuation due to AEs (n = 4).

Conclusions: The MC may improve motor and nonmotor symptoms in patients with PD and may allow for reduction of concomitant opioid medication use. Large, placebo-controlled, randomized studies of MC use in patients with PD are required.”

https://pubmed.ncbi.nlm.nih.gov/37191563/

https://journals.lww.com/clinicalneuropharm/Abstract/2023/05000/Medical_Cannabis_in_the_Treatment_of_Parkinson_s.3.aspx

“Objectives: Medical cannabis (MC) has recently garnered interest as a potential treatment for neurologic diseases, including Parkinson’s disease (PD). A retrospective chart review was conducted to explore the impact of MC on the symptomatic treatment of patients with PD.

Methods: Patients with PD treated with MC in the normal course of clinical practice were included (n = 69). Data collected from patient charts included MC ratio/formulation changes, PD symptom changes after initiation of MC, and adverse events (AEs) from MC use. Information regarding changes in concomitant medications after MC initiation, including opioids, benzodiazepines, muscle relaxants, and PD medications, was also collected.

Results: Most patients were initially certified for a 1:1 (∆9-tetrahydrocannabinol:cannabidiol) tincture. Eight-seven percent of patients (n = 60) were noted to exhibit an improvement in any PD symptom after starting MC. Symptoms with the highest incidence of improvement included cramping/dystonia, pain, spasticity, lack of appetite, dyskinesia, and tremor. After starting MC, 56% of opioid users (n = 14) were able to decrease or discontinue opioid use with an average daily morphine milligram equivalent change from 31 at baseline to 22 at the last follow-up visit. The MC was well-tolerated with no severe AEs reported and low rate of MC discontinuation due to AEs (n = 4).

Conclusions: The MC may improve motor and nonmotor symptoms in patients with PD and may allow for reduction of concomitant opioid medication use. Large, placebo-controlled, randomized studies of MC use in patients with PD are required.”

https://pubmed.ncbi.nlm.nih.gov/37071411/

https://journals.lww.com/clinicalneuropharm/Abstract/9900/Medical_Cannabis_in_the_Treatment_of_Parkinson_s.48.aspx

“Aim: Investigating molecules having toxicity and chemical similarity to find hit molecules. 

Methods: The machine learning (ML) model was developed to predict the arylhydrocarbon receptor (AHR) activity of anti-Parkinson’s and US FDA-approved drugs. The ML algorithm was a support vector machine, and the dataset was Tox21. 

Results: The ML model predicted apomorphine in anti-Parkinson’s drugs and 73 molecules in FDA-approved drugs as active. The authors were curious if there is any molecule like apomorphine in these 73 molecules. A fingerprint similarity analysis of these molecules was conducted and found tetrahydrocannabinol (THC). Molecular docking studies of THC for dopamine receptor 1 (affinity = -8.2 kcal/mol) were performed. 

Conclusion: THC may affect dopamine receptors directly and could be useful for Parkinson’s disease.”

https://pubmed.ncbi.nlm.nih.gov/36942739/

“A machine learning model was developed to predict AHR activity of anti-Parkinson’s and US FDA-approved drugs separately. The model predicted apomorphine in anti-Parkinson’s drugs, 73 molecules in FDA-approved drugs and tetrahydrocannabinol as active.”

https://www.future-science.com/doi/10.4155/fmc-2022-0181

“Δ⁹-tetrahydrocannabinol (Δ⁹-THC) exerts a direct neuroprotective effect in a human cell culture model of Parkinson’s disease”

https://pubmed.ncbi.nlm.nih.gov/22236282/

“Objectives: Cannabis has been proposed as a potential treatment for Parkinson’s disease (PD) due to its neuroprotective benefits. However, there has been no rigorous review of preclinical studies to evaluate any potential treatment effect. This systematic review was undertaken to provide evidence in support or against a treatment effect of cannabinoids in animal models of PD.

Methods: Databases were searched for any controlled comparative studies that assessed the effects of any cannabinoid, cannabinoid-based treatment or endocannabinoid transport blocker on behavioural symptoms in PD animal models.

Results: A total of 41 studies were identified to have met the criteria for this review. 14 of these studies were included in meta-analyses of rotarod, pole and open field tests. Meta-analysis of rotarod tests showed a weighted mean difference of 31.63 s for cannabinoid-treated group compared with control. Meta-analysis of pole tests also showed a positive treatment effect, evidenced by a weighted mean difference of -1.51 s for cannabinoid treat group compared with control. However, meta-analysis of open field test demonstrated a standardised mean difference of only 0.36 indicating no benefit.

Conclusion: This review demonstrates cannabinoid treatment effects in alleviating motor symptoms of PD animal models and supports the conduct of clinical trials of cannabis in PD population. However, there is no guarantee of successful clinical translation of this outcome because of the many variables that might have affected the results, such as the prevalent unclear and high risk of bias, the different study methods, PD animal models and cannabinoids used.”

https://pubmed.ncbi.nlm.nih.gov/36618606/

“Overall, this systematic review and meta-analysis provides evidence of the benefit of cannabinoid treatment in PD animal models, which warrants further investigations. This review supports clinical trial of cannabis or cannabis-based treatments in humans with PD.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9812814/