Parkinson’s disease is a degenerative disorder of the central nervous system mainly affecting the motor system. Symptoms are movement-related such as shaking, rigidity, slowness of movement and difficulty with walking and gait.

Recent years have brought a wealth of new scientific understanding regarding how medical marijuana or cannabis can be beneficial for treating Parkinson’s disease.

Thinking and behavioural problems may arise, with dementia commonly occurring in the advanced stages of the disease, and depression being the most common psychiatric symptom.

The disease progresses more quickly in older patients, and may lead to severe incapacity within 10 – 20 years. Older patients also tend to have muscle freezing and greater declines in mental function and daily functioning than younger people.

Medical Marijuana Efficiency

According to a recent study published in Clinical Neuropharmacology, participants smoking medical cannabis had significant improvements in motor disability and impairment. These results were found in addition to reported decreases in rigidity (stiffness or inflexibility), tremors (repetitive shaking), and dyskinesia (difficulty in performing voluntary movements), and improvements in pain and sleep disturbance. This study was flawed in that it included only 22 participants, there was no blinding to treatment (i.e. both the participants and researchers knew that they were using cannabis, which means that the results were potentially a result of “expectancy effects”), and they used a “within-subjects” design, which has well-documented weaknesses. Still, these results show that further study is appropriate and warranted.

In a study published in the Journal of Psychopharmacology in September 2014 found that treatment with 300 mg/day of the cannabinoid cannabidiol (CBD) in patients with Parkinson’s Disease, without dementia or comorbid psychiatric conditions (i.e. those occurring at the same time as the primary disease), increased well-being and quality of life compared to patients who had received the placebo (an inactive treatment used to attempt to control for “expectancy effects”).

However, there was no improvement in measures of motor (i.e. movement) and general symptoms, and no evidence for possible neuroprotective effects, a hindrance in the study was the minute number of participants, with only 21 participants split into 3 groups (placebo, 75 mg/day CBD, and 300 mg/day CBD). In spite of the lack of significance in certain measures and the small group, these results are impressive, especially given that the increase in well-being and quality of life resulted from use of a non-psychoactive cannabinoid.

Research into the relationship between THCV and tremors associated with Parkinson’s has suggested a significant reduction in erratic, uncontrolled movement.