According to a recent study published in Clinical Neuropharmacology, participants using smoked medical cannabis had significant improvements in motor disability and impairment. These results were found in addition to reported decreases in tremor (repetitive shaking), rigidity (stiffness or inflexibility), 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 PD, 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, and the sample size was small, 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 sample size, these results are impressive, especially given that the increase in well-being and quality of life resulted from use of a non-psychoactive cannabinoid.