Cannabidiol for Parkinson's disease symptom management

By Dr. Priyom Bose, Ph.D.Reviewed by Aimee MolineuxMay 17 2022

Parkinson's disease (PD) is a neurodegenerative disorder caused by the loss of nerve cells in a part of the brain called substantia nigra. This anomaly affects the level of dopamine. Dopamine is a neurotransmitter produced in the brain. In addition to serving as a reward center, it also controls many body functions, such as memory, movement, motivation, mood, and attention. Diseases such as Parkinson's, 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 rigidity, balance problems, and postural instability.

Cannabidiol, commonly known as CBD, is one of more than 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 community has increased.

Scientists have published a review study in the Journal for Nurse Practitioners that has focussed on various aspects of the use of cannabidiol in Parkinson's. 

To date, the direct cause of PD is still relatively unknown; however, it is suspected that the disease is caused due to a combination of genetic and environmental factors. Additionally, there is no standardized treatment available for PD because the symptoms of one PD patient differ from another. 

Review: Cannabidiol (CBD) Consideration in Parkinson Disease. ​​​​​​​Image Credit: Creativan / Shutterstock

Common Symptoms of Parkinson's Disease

Studies have shown that PD symptoms can develop over the years. Some of the common symptoms associated with lack of dopamine are bradykinesia, tremors, issues with gait, the rigidity of the limb, and postural instability. Additionally, patients with PD also suffer nonmotor symptoms that include depression, sleep disorder, cognitive impairment, constipation, excessive sweating, loss of sense of smell, hallucination, urinary urgency, pain, forgetfulness, and fatigue. Patients with PD are often more affected by non-motor symptoms than motor symptoms.

Previous studies have shown that PD patients also suffer from Lewy body dementia, a rare form of dementia caused by the accumulation of abnormal a-synuclein in substantia nigra neurons.

Management of Parkinson's Disease

Studies have shown that pharmacologic treatments have been effective in managing the disease's motor symptoms. In addition, these treatments have expanded the life spans of the patients. Commercially available dopaminergics can effectively activate or enhance dopamine levels in the brain. However, several side effects involved with the use of dopaminergics further complicate disease management. For instance, dopaminergics might interact with other drugs and elevate non-motor symptoms. Antidepressants, for instance, block dopamine and, therefore, interfere with medications used to treat motor symptoms. Therefore, PD treatment must be adjusted meticulously for each patient.

As PD progresses, the adverse effects of treating it accumulate, making it challenging to continue pharmacologic treatment. In addition, studies have shown that ongoing deaths of neurons affect the dopamine level, and hence, there is a high possibility of erratic performance of the drugs.

Some of the common nonpharmacologic approaches found to be effective in the earlier stage of PD include exercise therapy and speech therapy. Additionally, deep brain stimulation and cognitive behavior therapy have been found to be helpful when combined with pharmacological treatments.

Utilization 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% of tetrahydrocannabinol to avoid the risk of abuse or dependency. CBD products have been used for neurologic disorders, pain, insomnia, anxiety, headaches, and depression in the USA.

Preclinical studies have reported that CBD possesses antipsychotic, anticompulsive, panicolytic, antidepressant, and anxiolytic properties. A clinical trial revealed that administration of 300 mg/d of CBD improved mobility, communication, emotional state, body discomfort, and communication of PD patients compared with placebo treatment. A recent study has also stated that nonmotor symptoms of PD were substantially improved by CBD treatment. 

Notably, a recent animal model study has reported that CBD exhibited neuroprotective properties in patients with PD by reducing nigrostriatal degeneration and neuroinflammatory responses. This treatment has also improved motor performance. In addition, CBD treatment decreased the depletion of dopamine, provided anti-inflammatory activity, and slowed oxidative stress in animal models

Conclusion

Scientists have cautioned against the use of CBD in immunocompromised patients. This is because of the increased risk of weight loss, infection, and anemia. Additionally, owing to the complex pharmacodynamic and pharmacokinetic profile of CBD, it can interact with other drugs easily. Using CBD to treat Parkinson's disease is a relatively new area of research, and human clinical trials are necessary to confirm its long-term efficacy.

A major advantage of CBD medication, as compared to regular Parkinson's medication, 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. If experiencing any side effects, one 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 the current pharmacological treatments. The use of cannabidiol for therapeutic purposes is new, and further studies need to be conducted 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 built compared with a non-PD brain, separate studies are needed to assure successful results.