Marijuana & Parkinson’s

The second most common neurological illness in the U.S. is Parkinson’s disease.  Symptoms of this disease are tremors, slowness of movement, postural instability and impaired balance and coordination.  Marie Ellis gives information from a new study that suggests that symptoms of this condition could be improved with marijuana.

Prof. Zvi Loewy from the Touro College of Pharmacy in New York led a review that is published in the journal Parkinson’s Disease (PD).  It is noted that medical marijuana has been approved in various U.S. states to treat the symptoms of cancer, HIV/AIDS, glaucoma, chronic pain, seizures, cachexia and multiple sclerosis.

There has also been another recent study that suggests tetrahydrocannabinol (THC), the active compound in marijuana, reduced beta-amyloid levels in nerve cells.  This is a protein considered a hallmark of Alzheimer’s disease. About 1 million people are affected by PD in the U.S. This disease gets worse over time and occurs when a person’s brain stops producing dopamine.  This is a neurotransmitter that plays a key role in our movement, as well as our cognitive and psychological functions. Currently, there is no cure for the disease and treatments carry several limitations and do not slow progression of PD.  

The latest study says that research has indicated the endocannabinoid system plays an important role in PD as components of this system are highly expressed in the neural circuit of basal ganglia, which is part of a complex neuronal system.  This system organizes activities from certain cortical regions that are active in the movement control. Therapies out there were basically for motor symptoms, but Parkinson’s also has non-motor symptoms that greatly impact the quality of a person’s life.  The team conducted a thorough literature review on studies of marijuana. A chemical component of marijuana yields benefits in the wake of different PD symptoms and is the most compelling finding. Prof. Loewy notes that marijuana has been found to relieve pain in other disease and it should be studied for pain relief in people with PD.  About 50% of people with this condition are affected by pain.

According to the team, the cannabinoid compounds in marijuana bind to dopamine receptors to reduce the effects of reduced dopamine in the brain.  The compounds replace the normal compounds that are adversely affected by Parkinson’s.

It was also found that the anti-inflammatory and antioxidant effects of marijuana might prevent neuron damage.  Preventing neuron damage could slow PD progression.

There is a need for safer drugs to treat PD and cannabis may provide a viable alternative or addition to the current treatment of Parkinson’s disease.  There are risks to take into account including memory loss, increase osteoporosis risk and impaired blood vessel function. A study published in April suggested that marijuana use might reduce dopamine in the brain, so this should be taken into account as to how it could affect PD.  

Further studies are indicated to provide more data on efficacy, safety, pharmacokinetics and interactions of cannabinoids.  Some cancer patients are using marijuana for their pain and discomfort as well.

Dr Fredda Branyon