With medical marijuana now legalized in 33 states and Washington, DC, it is obvious that there is strong interest in its therapeutic properties. Researchers are testing marijuana, which is also called cannabis, as a treatment for many illnesses and diseases, including neurological conditions, with Parkinson’s disease (PD) high on the list. But despite several clinical studies, it has not been demonstrated that cannabis can directly benefit people with PD.
The Science Behind Marijuana
What is the science and pharmacology behind marijuana, and can it be used to treat Parkinson’s symptoms?
The endocannabinoid system is located in the brain and made up of cannabinoid receptors (a receptor is molecular switch on the outside of a cell that makes something happen inside a cell when activated) that are linked to neurons (brain cells) that regulate thinking and some body functions.
Researchers began to show enthusiasm to study cannabis in relation to PD after people with PD gave anecdotal reports and posted on social media as to how cannabis allegedly reduced their tremors. Some researchers think that cannabis might be neuroprotective— saving neurons from damage caused by PD.
Cannabinoids (the drug molecules in marijuana) have also been studied for use in treating other symptoms, like bradykinesia (slowness caused by PD) and dyskinesia (excess movement caused by levodopa). Despite some promising preclinical findings, researchers have not found any meaningful or conclusive benefits of cannabis for people with PD.
Researchers issue caution for people with PD who use cannabis because of its effect on thinking. PD can impair the executive function — the ability to make plans and limit risky behavior. People with a medical condition that impairs executive function should be cautious about using any medication that can compound this effect.
The Pharmacology of Cannabis
Marijuana contains more than 100 neuroactive chemicals that work with two types of cannabinoid receptors, type 1 (CB1) located in the brain and type 2 (CB2) located in the brain and peripheral immune system. Cannabinoids have powerful, indirect effects on these receptors, but researchers are unsure how. People with PD have less CB1 receptors than people who do not have PD. A boost to the CB1 receptor through an agonist, like marijuana, can improve tremors and may alleviate dyskinesia. Similarly, the other receptor, CB2, is also being studied to determine if it can modify the disease or provide neuroprotective benefits. However, a unified hypothesis does not currently exist for either receptor because there is too much conflicting data on the effectiveness of cannabinoids and these receptors.
Cannabis can contain two different types of molecules that interact with cannabinoid receptors: agonists and antagonists. An agonist is a drug that attaches to the same receptor as a natural chemical and causes the same effect. A dopamine agonist is a drug that is not dopamine, but attaches to the dopamine receptor. An antagonist is different as it attaches to the receptor, but blocks the action of the natural chemical. Medical marijuana can contain both cannabinoid agonists and antagonists. Recreational marijuana use is derived from its effects on agonists.
The varying amounts of cannabinoid agonists and antagonists in different marijuana plants makes cannabis studies difficult to conduct. When researchers study the effects of a medication, dosages are controlled and often set to a specific number of milligrams. When testing medical marijuana, the dosage administered can vary dramatically depending on the plant and method of administration.
THC is a primary component of marijuana. Cannabidiol is the other primary component. THC has a long latency of onset and cannot be easily measured for a therapeutic or medicinal dose. Medical marijuana studies primarily provide participants with THC and/or cannabidiol as a capsule, nasal spray or liquid formulation.
PD-Related Medicinal Marijuana Trials
The use of cannabinoids has been suggested to help with managing neurological and non-neurological conditions. Literature on medical marijuana is incredibly varied. Studies have not clearly supported the use of marijuana for PD. The clinical studies of cannabis as a PD treatment that have been conducted did not use the clinical trial gold standard of a double blind, placebo controlled trial design. Some studies had as few as five subjects.
While some results have been positive, the effects of medical marijuana are probably not completely understood, which is why more studies, especially those with more subjects, are needed. Most doctors don’t support study results because these studies do not meet minimum research standards.
Below are several PD-related medical marijuana studies that have been conducted to evaluate the use of cannabinoids:
- The Therapeutic Potential of Cannabinoids for Movement Disorders: clinical observations and trials of cannabinoid-based therapies suggest a possible benefit to tics and probably no benefit for tremor in dyskinesias or PD motor symptoms. Further preclinical and clinical research is needed to better characterize the pharmacological, physiological and therapeutic effects of this class of drugs in movement disorders.
- Cannabinoids Reduce Levodopa-induced Dyskinesia in Parkinson’s Disease: A Pilot Study: the authors demonstrate that nabilone, the cannabinoid receptor agonist, significantly reduces levodopa-induced dyskinesia in PD.
- Neurokinin B, Neurotensin, and Cannabinoid Receptor Antagonists and Parkinson Disease: evaluation of the effects of three antagonists on the NK3, neurotensin and cannabinoid receptors on the severity of motor symptoms and levodopa-induced dyskinesias after administration of a single dose of levodopa in 24 patients with PD. The study concluded that the drugs tested were safe, but did not improve Parkinsonian motor disability.
- The Endocannabinoid System as an Emerging Target of Pharmacotherapy: reviews the endocannabinoid system and its regulatory functions in health and disease.
Risks and Benefits for People with PD
There are risks and benefits associated with the use of cannabis for people with PD. Benefits include a possible improvement in anxiety, pain management, sleep dysfunction, weight loss and nausea. Potential adverse effects include: impaired cognition (impairment in executive function), dizziness, blurred vision, mood and behavioral changes, loss of balance and hallucinations. Chronic use of marijuana can increase risk of mood disorders and lung cancer.
Medical Marijuana and Legislation by State
Thirty-five states and Washington, DC have passed legislation allowing the use of marijuana-based products.
In some states where medical marijuana is legalized, consumers must register to possess and use cannabis. Other states require consumers to acquire a document from a physician stating that the patient has an approved condition. Under federal law doctors cannot prescribe cannabis, but many states authorize them to issue certifications that allow patients to obtain medical marijuana.
PD is listed as a qualifying condition for medical marijuana in Connecticut, Florida, Illinois, Louisiana, Massachusetts, Michigan, Mississippi, Missouri, New Hampshire, New Mexico, New York, Ohio, Pennsylvania and West Virginia.
Medical marijuana is legal in Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Hawaii, Illinois, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah, Vermont, Washington, West Virginia and Washington, DC.
Fifteen states have legalized the recreational use of marijuana, making it legal for adults over the age of 21 to legally consume marijuana without a doctor’s recommendation. Many of these states still differentiate recreational from medical marijuana. In some states, medical marijuana consumers may have access to specialized dispensaries, strains of marijuana and sales tax exemptions.
Recreational marijuana is legal in Alaska, Arizona, California, Colorado, Illinois, Maine, Massachusetts, Michigan, Montana, New Jersey, Nevada, Oregon, South Dakota, Vermont, Washington, and Washington, DC.
Multiple states, counties or cities have decriminalized certain marijuana-related offenses. In these areas, the possession of marijuana can be met with a citation — forgoing an arrest or criminal record — or no penalty at all.
For state by state guidance on marijuana legalization, medical laws and discrimination visit Norml.org/laws.
Parkinson’s Foundation Centers of Excellence and Medicinal Marijuana
The Parkinson’s Foundation, in partnership with Northwestern University researchers, studied attitudes about cannabis at 40 Centers of Excellence. To the best of our knowledge, this is the first study to provide data on the practices, beliefs and attitudes of expert PD physicians concerning cannabis use.
The results were interesting: most experts said they knew what cannabis did, but disagreed on the details. While there is no general agreement on what the benefits might be for people with PD, the survey confirmed that cannabis is a popular subject within Parkinson’s Foundation centers as 95 percent of neurologists reported patients have asked them to prescribe it.
Cannabis study results also included:
- Only 23 percent of physicians had any formal education on the subject of cannabis (such as a course or lecture), thus 93 percent of physicians want cannabis taught in medical school.
- Physicians reported that 80 percent of their patients with PD have used cannabis.
- Only 10 percent of physicians have recommended the use of cannabis to patients with PD.
- In terms of memory: 75 percent of physicians felt that cannabis would have negative effects on short-term memory and 55 percent felt that cannabis could have negative effects on long-term memory
- Only 11 percent of physicians have recommended use of cannabis in the last year
This graph shows how physicians expect cannabis would improve, worsen, or show no effect to PD-related symptoms given their expertise and observations of patients with PD.
The study emphasized that physicians would be more apt to use medical marijuana as a treatment if it was approved through regulation instead of legislation. Nearly all medications are only approved after passing a science-based evaluation proving their effectiveness in a process overseen by the U.S. Food and Drug Administration. Since cannabis has been approved through legislation rather than regulation, there are no labels, dosage recommendations or timing instructions that physicians can reference.
Is Medical Marijuana an Option for Me?
What’s next for a person with PD who wants to know if medical marijuana is an option? “Marijuana should never be thought of as a replacement for dopaminergic and other approved therapies for PD,” said Dr. Michael S. Okun, the Parkinson’s Foundation National Medical Advisor.
Research is still needed to determine how medical marijuana should be administered and how its long-term use can affect symptoms of PD. To keep patients safe, states that legalize medical marijuana will eventually need to develop training programs for doctors and medical teams that prescribe medical marijuana. Consult your doctor to see if medical marijuana is an option for you.
The Parkinson’s Foundation Consensus Statement on the Use of Medical Cannabis for Parkinson’s Disease is designed to help guide the PD community in making informed decisions about using cannabis for Parkinson’s. The statement is based on the input from 46 experts who attended the Foundation’s first-ever medical marijuana convening. Read it now.
Page reviewed by Dr. Bhavana Patel, Movement Disorders Fellow at the University of Florida, a Parkinson’s Foundation Center of Excellence.
With medical marijuana now legalized in 33 states and Washington, DC, it is obvious that there is strong interest in its therapeutic properties. Researchers are testing marijuana, which is also called cannabis, as a treatment for many illnesses and diseases, including neurological conditions, with Parkinson's disease (PD) high on the list. But despite several clinical studies, it has not been demonstrated that cannabis can directly benefit people with PD.
CBD: A Natural Remedy that Decreases Symptomatic Behaviors of Parkinson’s Disease?
Table of Contents
A healthy, natural alternative to traditional medications is becoming more and more accessible for persons suffering the effects of Parkinson’s disease. Studies show that CBD, a Cannabidiol also referred to as CBD-rich cannabis, may relieve debilitating symptoms of Parkinson’s. CBD is a natural compound found in cannabis sativa plants, with none of the adverse side effects of prescription medications and without the “high” effect from THC in marijuana. And while traditional medications may become less effective over time, or stop working completely, CBD users are hailing long-lasting benefits, with many giving up their pharmaceuticals for good.
CBD is also gaining momentum as a treatment for other health-related conditions including Alzheimer’s disease, epilepsy, anxiety, and chronic pain. Studies are ongoing, but returns indicate CBD is an exciting alternative to traditional medications.
Parkinson’s disease (PD) is a neurological disorder that affects one’s nervous system, with the average age of onset at 60. Simply stated, brain cells that produce the neurotransmitter dopamine, responsible for transmitting messages to the body in relation to movement, become damaged and die. This results in a variety of movement issues, which may include tremors, lack of facial expression, difficulty balancing, and stiffness of muscles. In addition, PD may develop into Parkinson’s disease dementia (PDD), which impacts one’s cognitive functioning, such as the ability to remember things, make good decisions, and pay attention.
Please note, dementia with Lewy bodies (DLB) presents with symptoms similar to PDD. However, with DLB, cognitive issues are present prior to one experiencing issues with movement. All of these diseases are progressive, meaning the symptoms become worse as time goes on, and unfortunately there is no cure.
Initially, symptoms of PD may be nearly unnoticeable and may include:
– Difficulty standing after sitting
– Lack of facial emotion
– Tremors (a slight shakiness of one’s hands)
– Bradykinesia (slowness of movement)
– Balance issues
One’s manner of walking changes as PD progresses. In fact, it is a gait so commonly seen that it has its own name: Parkinson’s (or Parkinsonian) gait. This is often characterized by a stooped posture, short steps that are more like shuffling of the feet (as if the individual is dragging them), and reduced arm movement or arms that do not swing when one is walking.
Persons with PD may experience other issues over time, including:
– Loss of smell
– Trouble swallowing
– Slurred speech
– Visual hallucinations
– Lack of judgement
– Difficulty concentrating
– Memory loss
Persons with PD may also suffer from depression, anxiety, apathy, irritability, pain, and difficulty sleeping. As mentioned previously, many people with Parkinson’s disease go on to develop Parkinson’s disease dementia.
Persons with PD and PDD often seek treatment in the form of prescription medications to alleviate the symptoms, frequently with adverse side effects including dizziness, drowsiness, blurred vision, nausea, diarrhea, vomiting, dry mouth, loss of appetite, heartburn, and more.
Potential Benefits of CBD
Exciting news about the therapeutic effects of CBD for persons with PD abounds. A recently published study from Brazilian researchers showed that CBD reduced anxiety and tremors that occurred during a public speaking test for people over 60 with PD. Subjects who took 300 milligrams of CBD before giving a speech (public speaking is a classic anxiety-inducer) had less symptoms than a control group who were given a placebo.
This builds on exciting previous findings. Because PD affects the brain’s ability to produce dopamine, researchers Alyssa S. Laun and Zhao-Hui Song from the University of Louisville, Kentucky, made an important discovery a few years ago when they found that CBD acts as an “inverse agonist” on CPR6 receptors found predominantly in the basal ganglia region of the brain, which connects to the cerebral cortex and brainstem, driving functions in our bodies including movement, learning, and emotion. This means CBD potentially responds within the receptors to provide therapeutic effects against the symptoms of PD. Any increase in dopamine levels would counteract the steady decrease of dopaminergic neurons experienced by those afflicted with PD.
Cannabinoid receptors run throughout our body as part of the endocannabinoid system regulating physiological operations including hunger, pain sensitivity, temperament, and memory. These natural receptors are affected in patients with PD. As analyses continue, CDB is demonstrating relief for tremors, psychosis, and problems sleeping. CBD may also reduce depression and anxiety, and relieve pain. A study at the Colorado School of Medicine has demonstrated relief of issues including tremors and difficulty sleeping. CBD studies are also showing it as effective in treating the psychosis that comes with PDD (Parkinson’s disease dementia). So far, patients are tolerant of low doses of CBD oil and report positive effects.
Numerous other studies echo CBD’s benefits:
– Researchers in Brazil had previously noted “Our findings point to a possible effect of CBD in improving quality of life measure in PD patients with no psychiatric comorbidities.” (Study)
– Researchers with the Department of Neuroscience and Behavior there concluded “preliminary data suggest that CBD may be effective, safe, and well tolerated for the treatment of the psychosis in PD.” (Study)
– And a different Colorado study concluded: “Cannabis was rarely used in our population but users reported high efficacy, mainly for nonmotor symptoms.”
These more recent revelations come on the back of federally funded preclinical studies published in 1998 documenting strong antioxidant and neuroprotective properties in CBD and THC, particularly in treating “neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and HIV dementia.” These promising findings led to a U.S. government patent on cannabinoids as antioxidants and neuroprotectants. Further, THC and CBD products are becoming mainstream as an increasing number of states legalize cannabis for medicinal and even recreational purposes. (For more on legalized CBD, see below.)
In June of 2018, the first FDA-approved CBD medication, Epidiolex, was approved to treat two rare types of epilepsy. While there are currently no CBD medications approved by the FDA specifically for Parkinson’s disease, one should not be discouraged, as research is ongoing. In 2017, the Salk University in California found that THC and other compounds found in cannabis, such as CBD, reduce the amount of amyloid beta, a plaque protein that is toxic in the brains of persons with Alzheimer’s disease. This is great news for persons with dementia because the removal of amyloid beta allows brain cells to survive. Amyloid beta not only kills neurons, it also causes inflammation and contributes to memory loss and other cognitive issues. This type of plaque is found in the brains of some persons with Parkinson’s disease dementia. In addition, some animal studies suggest that CBD might protect one against developing neurological disorders, such as Parkinson’s disease, in the first place.
Misperceptions & Myths
CBD Makes You Feel “High”
The effects of CBD and THC (Tetrahydrocannabinol), both cannabinoids that are extracted from cannabis sativa plants, are often confused. That said, both CBD and THC are known to have healing properties, and some researchers believe a combination of the two cannabinoids are very effective as a means of treatment. However, only THC produces a feeling of being “high”. Said another way, CBD-rich cannabis usage does not have any mind-altering effects. Given this fact, CBD is a desirable option for those that do not want to feel “high” from THC or certain prescription drugs.
CBD is a Regulated Product
Due to a lack of regulation when it comes to CBD products, there is no guarantee that a product containing a certain number of CBD mg (for instance 30mg) is the same as another stating it has the same mg dosage of CBD. Therefore, there may be a lack of consistency from one product to the next. A researcher at Penn Medicine in Philadelphia discovered that almost 70% of CBD products sold on the internet are under labeled or over labeled when it comes to the concentration of CBD within the product. Just 30% of the products bought contained a concentration of CBD within 10% of what the label indicated. For the best and most consistently produced CBD products, locally sourced medical CBD is recommended. This is because these products are held to a higher level of lab testing for strength, as well as impurities.
CBD has Sedative Properties
While some people may believe that CBD is a sedative, the truth is that it actually produces alertness without negatively impacting one’s sleep. Even if one takes a dose of 600mg of pure CBD, which is a very high dose, it still does not produce a sedating effect. However, one may take a CBD with a terpene (fragrant and flavorful essential oils found in plants) called myrcene, which is produced by several cannabis strains, that has sedating properties.
CBD is Legal in All States
As you will learn more below under “Legal Status of CBD in the U.S., CBD” is not legal in all 50 states. However, only in 3 states is it illegal: Idaho, Nebraska, and South Dakota. That said, CBD can be purchased legally online and delivered to all states. One can do so here.
Potential Risks of Use
Studies on CBD have shown that this form of treatment is usually tolerated well by users and is regarded as safe. There has also been no evidence for potential of abuse and/or dependence of CBD. That said, a few undesirable side effects have been noted, which include diarrhea, appetite changes, and tiredness. In addition, there may be dangerous drug interactions when CBD is combined with certain pharmaceutical medications. And the FDA warns that CBD can cause liver injury (as shown in some animal experiments with super high doses). The agency also says that long-term side effects remain unknown. Therefore, it is crucial that one speak with his/her physician prior to adding CBD to any medication regimen. In addition, one should monitor side effects upon use.
Forms of CBD Administration
There are a variety of options when it comes to administering CBD.
– Ingestible CBD, which is a very common means of consumption, and includes oils (CBD is mixed with what is called a carrier oil, such as hemp seed, coconut, and olive oil) and tinctures (CBD is in an alcohol solution).
– Sublingual consumption, whereby a few drops of oil or tincture is placed under the tongue for a few minutes, is often suggested. This is because the oil is absorbed by the sublingual tissue and quickly gets into the bloodstream. Therefore, the CBD is generally effective within a few minutes. One can also digest the oil or tincture directly or add to food, such as a smoothie.
– Oil capsules can be taken like pills.
– CBD edibles, like gummies, can take an hour before the effects of CBD kick in, and once it kicks in, the effects can be felt for 4 hours or even longer.
– Oils and tinctures can also be applied topically, meaning they can be applied to the skin. Like with digesting CBD, it can take an hour or so for the effects to be felt and will last for a few hours. This method of use is good for persons suffering from localized pain.
– One can also opt for CBD vape products (vaporizer pens), CBD inhalers, or smoke high CBD hemp strains. This method of inhalation allows users to feel the effects of CBD almost immediately and generally lasts a couple of hours.
There is not a preferred method of CBD administration for persons with Parkinson’s Disease. Rather, patients should choose a method with which they are most comfortable and one which is not hampered by tremors. If success with CBD is found, users should choose an administration method which can accommodate frequent and ongoing usage.
Legal Status of CBD in the U.S.
For the purposes of legality of CBD, it is important to be aware of the difference between hemp-derived CBD and marijuana-derived CBD. As previously mentioned, CBD is derived from both marijuana plants and hemp plants. Marijuana plants can contain as much as 30% THC, while hemp plants do not contain more than .03% THC. The percentage of THC in hemp plants is so low that it is impossible for one to get “high”, and therefore, the federal government has said it is legal and most states have made hemp-derived CBD legally available in their state. As far as CBD manufactured from marijuana, each state has its own specific laws that govern the legality of it.
- CBD produced from marijuana plants, as well as medical/recreational cannabis is legally available to users over the age of 21 in Alaska, California, Colorado, District of Columbia, Illinois, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, and Washington. In order to purchase these products, one must have a legal state ID.
- Marijuana-derived CBD and medical cannabis is legally available by prescription in an additional 28 states (as of February 2020). These include Arizona, Arkansas, Connecticut, Delaware, Florida, Georgia, Hawaii, Iowa, Louisiana, Maryland, Minnesota, Missouri, Montana, New Hampshire, New Jersey, New Mexico, New York, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, Utah, Virginia, West Virginia, Wisconsin, and Wyoming.
- CBD is also available with limited THC content (generally under .3% to under 5% THC) in the following states: Indiana, Kansas, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, and Texas.
- CBD in both forms is illegal in Idaho, Nebraska, and South Dakota.
How to Obtain CBD
The best place to buy CBD rich medical cannabis is from state licensed medical (and in some states, recreational) dispensaries. Alternatively, CBD can be purchased legally online here.
For convenience, many dispensaries also provide delivery services. Unfortunately, dispensaries are not legal in every state. Often times one can find hemp-derived CBD in local health stores. If taken once daily, a continuous regimen would cost approximately $2-$3 per day. As detailed in the following section, insurance will not cover the cost, therefore the daily cost would be out-of-pocket.
Insurance Coverage of CBD
Unfortunately, private health insurance companies will not cover the cost of CBD products with the exception of one product. This is Epidiolex, which as mentioned above, is FDA-approved for epilepsy. That said, please bear in mind that some Parkinson’s patients and their caretakers may find that high CBD strains of medical marijuana aren’t overly expensive and are safer (have less harmful side effects) compared to medications prescribed for Parkinson’s disease.
People frequently want to know if Medicare covers the cost of CBD products. As stated above, CBD (as well as THC) does not have adequate FDA approval. Therefore, Medicare does not cover the cost of such products, nor does Medicare allow it to be used towards a Part B (health insurance coverage) or prescription drug plan deductible. This is true for all conditions, not just for Parkinson’s Disease.
As with Medicare, Medicaid will not cover the cost of CBD products.
The VA will not directly cover the cost of products containing CBD. However, there are VA pensions, such as the basic pension and Aid & Attendance (A&A) Pension from which veterans or surviving spouses receive a monthly monetary benefit. Recipients of these pensions are able to use the money as they see fit, which means theoretically that one could use it towards purchasing CBD products. Learn more about these pensions here.
Learn how CBD-rich cannabis can decrease pain, tremors, anxiety, sleep, and other symptoms associated with Parkinson’s disease and Parkinson’s disease dementia, misperceptions about CBD, risk of use, legal status across states, and forms of administration.