A recent study published in the journal of Clinical Neuropharmacology sheds new light on the potential for medical cannabis to provide symptom relief for people living with Parkinson’s disease (PD).
There is a growing body of non-medical literature of people living with PD finding symptom relief from cannabis use. However, there exists only a small number of clinical trials that have explored the issue, with some reporting improvements to motor and nonmotor symptoms and others reporting no effects.
To add to this body of research, a group of Israeli researchers conducted telephone interviews with a group of PD patients who had used medical cannabis (MC) for at least three months to assess the effect of MC on PD symptoms as well as any adverse effects.
47 people participated in the study, of which 40 were men. The average age of the group was 64.2 years old, and the average PD duration was 10.8 years. The duration of MC use ranged from 3 to 84 months, with an average of 19.1 months. 10 patients reported increasing the MC dose for better effects (note: the number of reported responses from one question to another may deviate slightly from 47, as unclear responses were excluded from the statistical analyses).
First, the patient’s PD symptoms prior to MC treatment were assessed. Twenty-nine out of 45 (64.4%) had rest tremor, 24/45 (53.3%) had muscle stiffness, 24/45 (53.3%) had freezing of gait, 24/45 (53.3%) had gait disorders, and 22/47 (46.8%) had recurrent falls.
Varying degrees of depression were reported by 43/47 patients (10 mild, 20 moderate, and 13 severe). Varying degrees of memory impairment were reported by 33/44 patients (8 mild, 18 moderate, and 7 severe). Varying degrees of concentration problems were reported by 33/47 patients (8 mild, 17 moderate, and 8 severe). In addition, 31 patients reported experiencing chronic pain, and 31 patients reported having sleep disorders.
Effect of MC on PD symptoms
An overall reduction in complaints of falling was reported (from 22/47 to 6/18). A reduction in general muscle stiffness was reported by 32/44 patients, while 30/41 reported a reduction in muscle tremors. There were no reports of worsening of muscle stiffness or tremors. Pain reduction was reported by 35/43 patients, with the remainder reporting no change. An improvement in mood was noted by 35/46 patients, while one patient reported worsening of mood. An improvement in sleep quality was reported by 33/46 patients, while one patient reported diminished sleep quality. Only 10/40 patients reported a memory improvements, while 23 reported no change and 7 reported a worsening of memory.
Five out of 46 patients spontaneously stopped MC use between 3 and 12 months after initiating use. When asked about the reason for stopping MC use, two of these patients reported a lack of desirable effect, two others reported hallucinations, and the remaining patient reported postural instability.
No serious adverse effects or hospitalizations were reported by patients as a result of MC use. However, 28/47 patients noted some type of undesirable mental effect, such as confusion (8/47), anxiety (8/47), hallucinations (8/47), and short-term amnesia (3/46). One patient claimed to have developed psychosis as a result of MC use. In addition, 15/43 reported coughing, 2/43 experienced dyspnea (breathing difficulty or irregularity), 6/47 experienced dizziness, and 7/45 experienced unsteadiness.
Overall, 37/45 patients reported an improvement in their symptoms, while 2 reported no difference and 6 reported feeling worse following MC treatment.
In additional to quality of life improvements as a result of improvements in pain, sleep, and mood, the findings that MC resulted in a reduction in falls and improvements in muscle stiffness and tremors are very promising for people living with PD. Though there were numerous non-serious adverse effects reported, the continuation of MC treatment by most patients can be viewed as an indicator of the benefits and subjective satisfaction of the MC treatment. However, it is worth noting that 5/47 individuals included in the study, as well as 7/14 individuals from the group that was excluded from the final study population (a total of 12/61, or 19.7%) stopped MC treatment due to ineffectiveness or intolerable adverse effects.
It is also important to take the limitations of the present study into consideration—chief among them is that patients were not recruited through any systematic or randomized selection process, and all data was subjective and retrospective in nature.
Nevertheless, the authors conclude that “most of the users had found MC to improve their condition, and that MC treatment was safe, without major adverse effects.” The reported findings underscore the need for further clinical research on the use of MC for PD symptom relief, and suggest a possibility of developing safer and more effective drugs derived from cannabis. In the meantime, the researchers suggest that MC use should be limited to PD patients for whom existing medical treatments have not been effective.
Interested readers can find the original journal article here.
Featured image via Wikimedia Commons.