Parkinson’s disease (PD) is a neurodegenerative disease caused by the loss of nerve cells in a part of the brain called the substantia nigra. This anomaly affects the level of dopamine. Dopamine is a neurotransmitter produced in the brain. Besides serving as a reward center, it also controls many bodily functions, such as memory, movement, motivation, mood, and attention. Diseases such as Parkinson’s disease, restless legs syndrome and attention deficit hyperactivity disorder (ADHD) are associated with high or low levels of dopamine. Dopamine deficiency is associated with motor symptoms such as tremors, bradykinesia (slow movement), limb stiffness, balance problems, and postural instability.
Cannabidiol, commonly referred to as CBD, is one of over 100 chemicals found in the cannabis plant. CBD and THC (delta-9 tetrahydrocannabinol) are the two most important cannabinoids. Cannabinoids act on cannabinoid receptors throughout the body and brain, affecting how people feel, move, and react. The availability of cannabidiol in the United States has increased and interest in symptom management within the Parkinson’s disease community has increased.
Scientists have published a review study in the Journal for Nurse Practitioners who focused on various aspects of the use of cannabidiol in Parkinson’s disease.
To date, the direct cause of PD is still relatively unknown; however, the disease is suspected to be due to a combination of genetic and environmental factors. Additionally, there is no standardized treatment available for PD as one patient’s symptoms of Parkinson’s differ from another.
Review: Consideration of cannabidiol (CBD) in Parkinson’s disease. Image Credit: Creativan / Shutterstock
Common Symptoms of Parkinson’s Disease
Studies have shown that symptoms of PD can develop over years. Some of the common symptoms associated with lack of dopamine are bradykinesia, tremors, gait problems, limb stiffness, and postural instability. Additionally, patients with PD also suffer from non-motor symptoms including depression, sleep disturbance, cognitive impairment, constipation, excessive sweating, loss of sense of smell, hallucinations, urinary urgency, pain, forgetfulness and fatigue. Patients with PD are often more affected by non-motor symptoms than by motor symptoms.
Previous studies have shown that Parkinson’s patients also suffer from Lewy body dementia, a rare form of dementia caused by the accumulation of abnormal a-synuclein in neurons of the substantia nigra.
Management of Parkinson’s disease
Studies have shown that pharmacological treatments have been effective in managing the motor symptoms of the disease. In addition, these treatments have extended the lifespan of patients. Commercially available dopaminergics can effectively activate or increase dopamine levels in the brain. However, several side effects related to the use of dopaminergics further complicate the management of the disease. For example, dopaminergics can interact with other medications and elevate non-motor symptoms. Antidepressants, for example, block dopamine and therefore interfere with medications used to treat motor symptoms. Therefore, the treatment of PD must be carefully adjusted for each patient.
As PD progresses, the adverse effects of its treatment accumulate, making it difficult to continue pharmacological treatment. Moreover, studies have shown that the continuous death of neurons affects the level of dopamine and, therefore, there is a high possibility of erratic drug performance.
Some of the common non-pharmacological approaches that have been shown to be effective in the early stage of PD include exercise therapy and speech therapy. Additionally, deep brain stimulation and cognitive behavioral therapy have been shown to be helpful when combined with pharmacological treatments.
Use of cannabidiol (CBD) in patients with Parkinson’s disease
Cannabidiol (CBD) is used as an alternative therapy for the treatment of PD. CBD is a phytoconstituent extracted from Cannabis-sativa. Typically, CBD products contain less than 0.3% tetrahydrocannabinol to avoid the risk of abuse or addiction. CBD products have been used for neurological disorders, pain, insomnia, anxiety, headaches, and depression in the United States.
Preclinical studies have reported that CBD has antipsychotic, anticompulsive, panicolytic, antidepressant, and anxiolytic properties. A clinical trial found that administration of 300 mg/d of CBD improved mobility, communication, emotional state, body discomfort, and communication in patients with PD compared to placebo treatment. A recent study also indicated that non-motor symptoms of PD were significantly improved by CBD treatment.
Notably, a recent study in an animal model reported that CBD exhibited neuroprotective properties in patients with PD by reducing nigro-striatal degeneration and neuroinflammatory responses. This treatment also improved motor performance. Additionally, CBD treatment decreased dopamine depletion, provided anti-inflammatory activity, and slowed oxidative stress in animal models.
Scientists have warned against using CBD in immunocompromised patients. This is due to the increased risk of weight loss, infection and anemia. Additionally, due to CBD’s complex pharmacodynamic and pharmacokinetic profile, it can easily interact with other medications. Using CBD to treat Parkinson’s disease is a relatively new area of research, and human clinical trials are needed to confirm its long-term effectiveness.
A major advantage of CBD medications, over regular Parkinson’s medications, is its lack of time restrictions. There are a number of side effects associated with CBD, including dizziness, confusion, drowsiness, and difficulty concentrating. When taking CBD, it is important to limit or avoid alcohol. In case of side effects, you should stop taking CBD products.
The complexity of PD has led to the development of a wide variety of treatment options aimed at targeting as many of these debilitating symptoms of this progressive disease while minimizing the adverse side effects associated with current pharmacological treatments. The use of cannabidiol for therapeutic purposes is new and further studies are needed on its safety in patients with Parkinson’s disease. CBD has been shown to have positive effects in numerous studies, but due to the differences in how the PD brain is constructed compared to a non-PD brain, separate studies are needed to ensure positive results.
- Kim, H. et al. (2022) Consideration of cannabidiol (CBD) in Parkinson’s disease. The Journal of Nurse Practitioners. https://doi.org/10.1016/j.nurpra.2022.04.006https://www.sciencedirect.com/science/article/pii/S1555415522001398