By: Elements of Green 

Many Parkinson’s patients have asked about the role of CBD (cannabidiol) might play in treating symptoms of the disease. People around the world have discovered that CBD oils, tinctures, creams, edibles, and even vape products help them with chronic and acute pain.  CBD also helps many people with sleeping issues, anxiety, and even nausea.

Parkinson’s patients often have symptoms which react well to CBD either as a direct symptom of the disease or as a side effect to one or more of the medications used to treat Parkinson’s. To get a fuller understanding of how CBD might help Parkinson’s patients get relief and of the important discussions Parkinson’s patient should have with their doctors before beginning to use CBD, this article reviews Parkinson’s disease and common treatments for it and discusses how CBD might relieve the symptoms of Parkinson’s patients. We look in detail at the relationship between CBD and Parkinson’s disease.

An older lady washing her hands.

About Parkinson’s Disease

Parkinson’s disease is a neurodegenerative condition which affects the portion of the human brain which controls body movements.  It is a progressive disease, which means that the symptoms don’t all start at once with a constant severity.  Instead, the symptoms start off slowly and become worse over time.  Parkinson’s patients suffer from impaired mobility, muscle rigidity, and tremors.   Parkinson’s base cause is that the brain cells which produce a neurotransmitter called dopamine deteriorate and die.  Dopamine is the main neurotransmitter which allows the brain to communicate its intent to move the body to the muscles which actually perform the action.  Unfortunately, other neurotransmitters are also lost, so simply replacing dopamine in Parkinson’s patients does not improve the condition for all patients.  Increasing dopamine levels does help many patients, but direct application of dopamine does not work. Instead, patients must take one more drugs which induce the body to produce more of its own dopamine or to conserve the dopamine that it does produce.

In addition to the motion-related symptoms of Parkinson’s, many patients suffer from pain, anxiety and depression.  Another very serious non-motor symptom is psychosis. Half of all Parkinson’s patients develop symptoms like hallucinations or delusions either directly or because of one or more medicines they take to help with the disease.[i]

A illustration of Brain connections being made.

The causes of Parkinson’s are unclear, though age is a factor. Most people do not develop Parkinson’s until after the age of 60.  Parkinson’s has no cure, but there are a variety of medications which can moderate the symptoms for a long time, increasing the quality of life for Parkinson’s patients.[i]

Current Parkinson’s Treatments

The most common Parkinson’s treatment is a drug called levodopa.  It is a chemical precursor to dopamine and it helps the body produce more dopamine.  Levodopa can cause nausea, so it is usually prescribed with another drug which moderates the body’s reaction to levodopa.  Levodopa also has other side effects like psychological effects, sleep problems, loss of appetite, and low blood pressure.

Other common treatments include:

  • COMT inhibitors: COMT (catechol-O-methly transferase) inhibitors are not used in isolation, but along with levodopa.  It inhibits the action of COMT, which is a brain chemical which caused dopamine to break down.  Less dopamine broken down means more dopamine available for the body to use to control muscle function. Side effects of COMT inhibitors include the same ones levodopa can cause, and using the two kinds of drugs together can make those side effects much worse.  COMT Inhibitors can also causea liver damage
  • MAO-B Inhibitors: The mechanism of a MAO-B inhibitor is different from that of COMT inhibitors, but the result is the same. MAO-B inhibitors block the action of MAO-B (monoamine oxidase type B), a brain enzyme which causes dopamine to break down. MAO-B inhibitors related to MAO-A inhibitors which are commonly used to treat depression. That means that people taking some anti-depressive medications are not suited for MAO-B inhibitors.
  • Dopamine agonists: An “agonist” is a drug which activates certain parts of a cell.  A dopamine agonist imitates dopamine.  These drugs essentially fool the brain into thinking it has more dopamine available than it really does. Side effects of dopamine agonists include several of the same side effects as levodopa. It can also cause blurred vision, sleepiness and fainting, headaches, and swollen muscles.  One side effect can be compulsive behavior – people with a history of problem gambling, alcohol abuse, nicotine abuse or other compulsive behaviors must be monitored carefully. Older dopamine agonists can cause serious heart problems but the newer ones do not have this side effect.
  • Amantadine: Amantadine was originally developed as an antiviral to combat influenza but doctors noticed that it helped Parkinson’s patients with reduced tremors and less muscle stiffness.  Scientists do not yet know exactly how Amantadine works but it seems to slow down the rate of cell loss in the brain.  The effects of Amantadine are often small relative to other Parkinson’s treatments, so it is not usually a first choice, instead being used when other drugs are not effective.[ii]

CBD’s Possible Role in Parkinson’s treatments.

CBD and Parkinson’s disease: CBD does not cure Parkinson’s disease.  There is currently no cure for Parkinson’s.  There is some evidence that CBD may help with some of the effects of Parkinson’s disease or with the side effects of prescribed Parkinson’s drugs.  CBD has been well-tolerated by millions of users but because of the lack of specific studies, there is a possibility that CBD may interact negatively with some Parkinson’ treatments. Accordingly it is very important that patients talk to their physicians before beginning to use CBD for a Parkinson’s symptom or side effect.

An older lady eating yogurt.

CBD is in the early stages of rigorous scientific study. Until recently, it was difficult or illegal to obtain CBD even for research institutions and many institutions were legally prohibited from doing research on CBD.  However, many of the effects which non-Parkinson’s patients report from using cannabidiol may also help Parkinson’s patients and there are some tantalizing studies which suggest that CBD may provide a direct effect to some patients.

Many people who use CBD report that it helps them reduce anxiety and depression, which are common non-movement symptoms of Parkinson’s.

Pain is another common symptom of Parkinson’s which CBD may help. Not only can Parkinson’s patients develop pain directly from the disease, the normal skeletal pain which sometimes comes with aging can be worse with Parkinson’s disease.

Nausea and vomiting are side effects to many Parkinson’s drugs and CBD helps some users with those symptoms.

Direct Effects for Parkinson’s Patients

CBD research is in its early stages, so there are no confirmed studies which indicate CBD as a direct treatment for Parkinson’s.  However, some early research and smaller studies indicate there might be direct benefits to Parkinson’s patients who take CBD.  In Brazil, a trial published just a few months ago demonstrated that Parkinson’s patients who took high dosages of CBD had less anxiety and reduced severity of tremors when they took a simulated public speaking test.[i]

Studies by the same group of scientists found that large dosages of cannabidiol resulted in patients reporting an improved quality of life and that CBD might also help Parkinson’s patients with REM sleep behavior disorder (RBD).

Another study from 2009 indicated that Parkinson’s patients who took CBD for four weeks in addition to their usual therapy experienced a significant decrease in psychosis symptoms.[ii]

These were all small studies and the results should be seen in that context, but none of the patients in the studies had an adverse effect and many saw improvements in symptoms of Parkinson’s or in the side effects of Parkinson’s medication.

Parkinson’s patients should discuss CBD with their doctors before beginning to use CBD.

CBD for Parkinson’s in the Future

Another study from 2017 found that CBD may act as an inverse agonist (an inverse agonist induces a reaction to a cell which is opposite to that of an agonist) on a nerve cell receptor called GPR6.  This is important for two reasons. The first is that CBD is mostly associated with the CB1 and CB2 receptors so if it has effects on other receptors it may increase the potential therapeutic benefits of CBD generally.  The other reason is that so far scientists have not found an internal inverse agonist for that receptor.  The GPR6 receptor is associated with Parkinson’s disease.  So far no one has demonstrated a direct therapeutic benefit by the mechanism the scientists discovered, so it is important not to place too much emphasis on this study, but it does indicate a potential route of future research.

The biggest news may be yet to come.  Parkinson’s UK, the largest funder of Parkinson’s research in Europe, has created a partnership with King’s College London to fund a Phase II clinical trial to investigate CBD as a treatment for hallucinations and delusions among Parkinson’s patients.  This study is a large-scale and more rigorous investigation of the findings from the 2009 study above. The lead researcher is one of the world’s leading experts in research involving cannabis and psychosis.[iii]

What Form Of CBD is Best?

Patients who choose to use CBD to treat symptoms of Parkinson’s or a side effect of Parkinson’s medication must decide several things.  First, they have to decide what form factor they choose for CBD.  Second, they need to decide whether they want to take pure CBD, CBD combined with other psychoactive cannabinoids, or CBD with those other cannabinoids and with THC, the part of cannabis which makes users high. Finally, they must choose a dosage.

How to Take CBD

The answer to the first question is likely to be common among Parkinson’s patients.  Overwhelmingly, Parkinson’s patients that try CBD like taking CBD oil, CBD tinctures, or CBD capsules. The vast majority of the studies using CBD for Parkinson’s patients administered the CBD in these ways.  However, there have recently been advances in product development among CBD producers and cannabidiol is now available as edible products such as CBD gummies, powders for beverages or chewing gum. Parkinson’s patients may also choose CBD vaping products, an increasingly popular way for people to take CBD.  Finally, it is possible to purchase creams and balms which contain CBD.  These products are most appropriate for isolated areas of pain, so they are unlikely to be the most helpful method of consumption for most Parkinson’s patients, but some users may find them beneficial.

Medical Cannabis, Full-Spectrum CBD, or Purified CBD?

The second question is about what other cannabinoids a CBD user wants to combine with the CBD for the best effect.  Many users want CBD combined with significant amounts of THC, the compound in cannabis which causes a psychoactive effect.  Those products are highly regulated in the UK and in Europe and require a doctor’s prescription or referral.

More commonly, patients choose a naturally derived CBD product made from hemp.  This kind of cannabidiol has trace amounts of THC, under .2% in most countries and not enough to make the user high, and it also has other non-psychoactive cannabinoids like CBA, CBG, and CBN.  The combination of cannabinoids causes an “entourage effect” which increases the effectiveness of the CBD for many users. These “full-spectrum” CBD products are also the most popular and easiest to find.  It is important to purchase full-spectrum CBD products from a trusted supplier which tests its products independently so that the patient gets safe and accurate products.

Some patients may benefit from purified CBD.  This kind of CBD product is also usually derived from natural hemp, but it has been specially screened to remove all traces of THC and of other cannabinoids.

Which kind of product a Parkinson’s patient chooses, whether it is THC cannabis with CBD, CBD with trace amounts of other cannabinoids, or purified CBD, is a discussion patients should have with their doctors.

How Much CBD Should a Parkinson’s Patient Take?

Dosage is also a subject Parkinson’s patients should discuss with a physician.  Most CBD products are available in a variety of doses, and of course patients can increase the CBD they use by increasing the amount of a product they consume. The precise dosage depends on the patient’s body weight, the severity of symptoms, other medications a patient might be taking, and other factors, which is why a discussion with a physician is so important.

Next Steps for Parkinson’s Patients

Parkinson’s patients considering CBD should consider which symptoms they have which might be helped by CBD.  They should then talk to their doctor about their plans.  When they have that discussion, they should have questions about potential drug interactions, about the emerging studies which indicate that CBD may eventually be a direct therapy for Parkinson’s disease, and about the best way for the patient to take CBD and about the appropriate dosage for their current condition.