Parkinson’s disease (PD) is a chronic degenerative nerve disorder, and approximately 50,000 new cases arise each year as our population ages. The cause of Parkinson’s is believed to be related to a defect in neuronal cells to produce the neurotransmitter dopamine, a vital and necessary component chemical of our normal functioning nervous system. Parkinson’s patients can have a myriad of relatively specific symptoms which include uncontrolled shaking of the extremities, muscle tremors, loss of control or balance issues, difficulty speech or swallowing, and often mental issues or memory recall problems… As a neurological disease, the symptoms can progress and worsen with time, so treatment is indicated –traditional pharmaceutical drugs which currently are in use are fairly effective, but fall short of a cure and may have adverse side effects.
Can medical cannabis have a beneficial effect to help these patients? The purpose of this article is to help find an answer to this question. A similar disease, Alzheimer’s, may also hold some clues to help answer this question, as it is also a neurologic disease. Also, with the wide variety of cannabis products available and methods of administration expanded, there are a lot of possibilities for cannabis to exert a beneficial, if not curative, effect against this disease. It is also important to consider is that some studies on this topic indicate that any benefits obtained may take several months or longer to be realized by the patient once cannabis therapy is initiated.
Parkinson’s disease is listed as a qualifying condition for medical cannabis in several states, but the clinical studies that prove its usefulness are lacking and results are mainly anecdotal. Nonetheless, patients in four major research studies from 2014 to 2017 indicate upon questionnaire that they experienced beneficial results from using cannabis with PD. These benefits included reduced tremor, reduced muscle stiffness, reduced pain, elevated mood, and improvement in overall symptoms of the disease.
However, it is important to note that there were also several adverse incidents reported in about 50% of the patients. These include attention and memory problems, confusion, anxiety, cough, dizziness, psychosis, and breathlessness. Many of these adverse effects can be mitigated by proper care, follow up, and communication with a skilled neurologist and/or cannabis prescriber. Dosage, techniques, and the balance of THC and CBD can be adjusted as needed to get the best chance for successful therapy. Very important to stress that these PD patients require regular, routine medical care – and that cannabis and its derivatives should be used as needed only as a supplemental therapy. But because traditional therapy is not fully effective and often has detrimental side effects, cannabis is a viable option for some PD patients.
Therapy using cannabis in this disease currently appears to take weeks to months in some cases to show improvements recognized by the patients, so patience and treatment longevity is required. Once a suitable technique is selected, which can vary for each patient, treatment should last between one and three months before a decision on effectiveness is reviewed. During this period dosage and composition of cannabinoids can be varied as needed based on symptomatology and responsiveness to therapy. Both CBD and THC may be effective.
Cannabis has an effect on motor and non-motor symptoms of PD. This effect can regulate the dopaminergic, adrenergic, serotonergic and neuroprotective systems inherent in the disease. The CB1 and CB2 cannabinoid receptors may play a role, as the CB1 receptor stimulation may account for some degree of cognitive impairment (a negative side effect) but also to stimulate dopaminergic transmission, and stimulation of the CB2 receptor accounts for microglia activation in the brain. This stimulation may play a role in neuroprotection and reduced inflammation (a beneficial effect). In PD, there is a loss or reduction of dopaminergic neurons in the brain, and this can cause the motor impairments in PD. These include resting tremor, bradykinesia (slow movement), rigidity, and muscle instability. Cannabis has been shown in molecular studies to modulate dopaminergic neurons in beneficial ways, but more human trials are needed. The interaction of the cannabinoid and dopaminergic system may respond to cannabis the same way that the neurons respond to levodopa (one current drug commonly used to treat PD). This is a positive effect and indicates there is interaction between cannabinoids and the dopamine system.
Another symptom of PD is pain, and exogenous cannabinoids seem to activate the TRPV1 receptors with the result that it can increase the frequency of excitatory post synaptic currents of dopaminergic neurons, and thereby reduce pain signaling. Oxidative stress and inflammation can cause neuronal cell death seen in PD as well as in other neurodegenerative disease like Alzheimer’s, depression, dementia, and migraines. Through stimulation of the CB2 receptor, cannabinoids have been shown to modulate the activity of the microglia cells whose activity is perturbed in PD.
In answer to the question about cannabis and PD, here is a summary:
*Molecular mechanisms indicate that cannabinoids can help regulate numerous systems that are prevalent and functioning improperly in Parkinson’s Disease
*Clinical placebo controlled studies are lacking at this time
*Most studies are anecdotal and rely on questionnaires concerning improvements of symptoms and perceived benefits – and reports indicate in the majority of patients an improvement in one or more symptoms were common
*Some studies have shown that smoked cannabis can be more effective on pain and tremor than vaped cannabis. Side effects of cannabis therapy need to be monitored closely in this disease, and smoking of cannabis introduces dosing and absorption issues.
*Individual responses may vary based on severity of disease and the type, quantity, method of use, and specific cannabinoid content that is ingested.
*PD is a neurodegenerative condition with limited treatment options, so a new approach with broad spectrum application such as cannabis may offer enough improvement in some of these patients to allow for cautious optimism and continued research. It is currently possible that some PD patients will show an improvement using cannabis in both motor and non-motor areas, but due to the large number of cannabinoids and techniques of dosage and administration there is no clear roadmap. Trial and error will certainly play a role in therapeutic treatment of this disease until more parameters and guidelines are developed.
However, due to the relatively benign and non-harmful effects of using cannabis, patients have the option to use Cannabis for PD currently in Maryland. If used under proper guidance, it is possible some beneficial effects may be seen, while mitigating any negative side effects.
Dr. Stanley R. Manstof
MMCC Certified Provider
Member Americans for Safe Access
International Cannabinoid Research Society
Certified Patient Caregiver
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