By Luke Sholl

Parkinson's disease is a degenerative disorder that can be very debilitating. It is thought that Parkinson's affects as many as 1 in 500 people. Symptoms begin gradually but worsen over time, starting with a loss of fine motor skills and leading to problems with tasks such as walking and talking. Sufferers may also experience mental and behavioural changes. Both men and women can get Parkinson's, however the disease seems to affect roughly 50% more men. Age is a significant risk factor, with most people developing the disease at around 60 years old.

While there is currently no cure, numerous treatments and therapies help sufferers lead as full and active lives as possible. Many complementary therapies are claimed to potentially benefit PD sufferers, including cannabis. However, few are medically approved.

So, what exactly is it about cannabis that makes it an intriguing candidate for easing Parkinson’s symptoms? And what does medical science have to say on the subject?

What Is Parkinson's Disease?

Parkinson's disease (PD) is a neurodegenerative disorder. This means it is characterised by degeneration of the nervous system—particularly the neurons in the brain. Symptoms of PD typically develop slowly over a matter of years. The advancement of symptoms can differ from one person to another due to the diverse nature of the disease.

  • Why Parkinson's Disease Occurs

Parkinson's disease materialises when nerve cells (neurons) in an area of the brain called the basal ganglia become impaired or die. This causes many problems in the body, as the basal ganglia controls movement. When functioning normally, these neurons produce an essential brain chemical known as dopamine. When impaired, they create less dopamine, which is what causes the physical symptoms of Parkinson's. At present, scientists do not know what causes these neurons to stop working.

What Is Parkinson's Disease?

How Parkinson's Affects the Body

People with PD can experience various symptoms, classed into movement-related "motor" symptoms and non-movement related "non-motor" symptoms.

Below we highlight some of the most prevalent.

  • Tremors

The characteristic Parkinson's tremors occur mainly at rest. When moving the hands, the tremors may lessen or disappear. Tremoring of the hands is also known as "pill-rolling", as it looks like you are continuously rolling a pill between your thumb and finger. Tremors can also appear in the lower lip, jaw, or legs, interfering with routine daily tasks. Some people also report a tremoring sensation inside the chest, abdomen, or limbs. In the early stages of PD, tremors typically only affect one side of the body. Stress, tiredness, or extreme emotions can temporarily worsen tremors.

  • Bradykinesia

Bradykinesia is slowness of movement, and includes reduced reflexive movements like blinking or arm swinging when you walk. Bradykinesia also causes difficulty starting actions, such as getting up out of a chair and slowness in bodily actions. The impression of unnatural stillness or a reduction in facial expression is another primary feature of bradykinesia.

  • Rigidity

Stiffness is the third telltale symptom doctors use to make a Parkinson's diagnosis. Rigidity is experienced as stiffness of the arms or legs beyond what would be expected from typical ageing or arthritis. Stiffness can contribute to a decreased range of motion, making it hard to relax, negatively impacting sleep, and leading to aching and pain in the muscles or joints. Rigidity can also affect the torso and facial muscles.

  • Balance Problems

Postural instability is the least treatable of the primary motor symptoms of PD. In an attempt to avoid falls, regular exercising is recommended to improve balance. Aside from this, physical therapy can be beneficial.

  • Non-Motor Symptoms

Non-motor symptoms are also prevalent in people diagnosed with PD. Examples include apathy, depression, constipation, sleep disorders, loss of sense of smell, and cognitive impairment.

How Parkinson's Affects the Body

Cannabis and Parkinson's Disease

There is little scientific evidence to prove that complementary therapies slow down, halt, or reverse PD. However, many people with the condition have reported positive experiences from experimenting with them. The goal of these interventions is to help in the management of symptoms, easing pain, reducing stress, and improving quality of life.

Complementary therapies include physical, occupational, and speech therapies, mind and body practices such as yoga and meditation, manipulative treatments like massage and acupuncture, and energy therapies such as reiki and qigong. Of course, alternative holistic systems like Ayurveda and traditional Chinese medicine are also utilised by some.

As Parkinson's is a condition of the central nervous system, and cannabis affects the central and peripheral nervous systems, the plant’s constituents are also being explored for their impact on PD.

  • How Does Cannabis Affect the Body?

Cannabis influences the body through the endocannabinoid system (ECS), an essential regulatory system that uses cannabinoid receptors, neurotransmitters (known as endocannabinoids), and enzymes to influence the central and peripheral nervous systems, among others.

The ECS is implicated in many processes and functions, such as mood, memory, sleep, and appetite—and its dysregulation[1] has even been implicated in Parkinson’s disease, among other neurodegenerative disorders.

When cannabis enters the body, it works to "activate" these receptors and endocannabinoids, altering normal neurotransmitter activity in the body and potentially influencing various aspects of the ECS.

Different cannabis constituents can stimulate unique responses through their interaction with the ECS. For example, while THC binds to CB1 receptors with great affinity, CBD has a more indirect effect.

How Does Cannabis Affect the Body?
  • Research on Cannabis for Parkinson’s Disease

With the above in mind, we can take a look at the research on cannabis for Parkinson’s directly, as well as the potential of specific cannabinoids.

To start, a 2017 study[2] asked participants to report the effects of using medical cannabis for symptoms of Parkinson’s disease, as well as any adverse events, over a period of at least three months. As the data collected is subjective, it cannot be considered true evidence of a correlation, but participants generally reported improvements in symptoms when using cannabis, and noted few adverse events. The authors state that the goal of the study is to support the development of “safer and more effective drugs derived from Cannabis sativa”.

A 2020 review[3] sought to assess the efficacy of cannabis as an alternative therapeutic for Parkinson’s disease, specifically observing the factors “hampering” its use in clinical practice of PD. Drawing upon 14 studies, only five of which were randomised controlled trials, the authors of the review noted that, despite some positive study results, there was still insufficient evidence to recommend cannabis as a Parkinson's treatment.

Additional research[4] has sought to determine the medicinal efficacy of cannabis for motor symptoms such as bradykinesia, rigidity, tremors, sleep issues, and pain, as well as non-motor symptoms[5] such as memory, mood, and fatigue.

Despite these findings, medicinal cannabis remains a contentious subject. Those living with PD should always discuss treatment options with their doctor before trying anything new.

Now, let's take a look at the potential of specific cannabinoids; namely, THC and CBD.


According to a 2017 review[6] entitled “Pros and Cons of Medical Cannabis use by People with Chronic Brain Disorders”, in PD studies on animals, THC has been shown to improve markers associated with activity and hand-eye coordination. The review also highlights a clinical study of 22 PD patients, which claims that medical cannabis use seemed to support improvements in motor symptoms such as bradykinesia, resting tremor, rigidity, and posture, as well as non-motor symptoms such as insomnia and pain.


CBD has received increasing study for its potential as an antioxidant and neuroprotective agent, not to mention its anxiolytic potential. A 2020 study[7] pitched CBD against anxiety and tremors in patients with PD over 60, opening up the gates for further randomised controlled trials.

A randomised, double-blind, placebo-controlled study[8] is currently underway, testing the “Tolerability and Efficacy of Cannabidiol (CBD) on Motor Symptoms in Parkinson's Disease”. This will help to paint a clearer picture of the effects of CBD on the primary symptoms of Parkinson’s, while other studies continue to explore its impact on other aspects of PD, such as psychosis[9].

How is Medicinal Cannabis Used?

Although there are no comprehensive guidelines for using cannabis in the realm of Parkinson’s, in general, users have the following options:

Each intake method works differently in the body. If you smoke or vaporize cannabis, you’ll feel the effects within minutes, while it can take one to two hours to feel the results if you eat it.

Smoking cannabis may have more side effects than other consumption methods. Short-term results are connected to the smoke itself. This includes irritation of the lungs, coughing, and other respiratory ailments. Over time, cannabis smoke may lead to heart problems or aggravate existing heart conditions. However, there are currently no clinical studies that show a direct relationship between cannabis and cardiovascular issues.

If you consume cannabis as an edible product or an extract, be wary of the dose. Edibles may take longer to kick in, but they’re also known to be much stronger and longer-lasting in effects than smoking.

Moreover, cannabis concentrates will hit you quickly like smoking, but can be much stronger in impact.

Cannabis for Parkinson's — More Research Is Needed

Clinical trials on the efficacy of medicinal cannabis have been limited in the past. Critiques of the current research support the opinion that more studies are needed to fully understand the long-term clinical effects of cannabis, including in Parkinson’s disease. Without further exploring dosage and adverse events, scientific evidence on the therapeutic role of the herb will remain in question.

There are currently many hurdles in controlling the quality and dosing of cannabis. Unless the ruling governments of powerful countries remove cannabis from its controlled substance status, research, access, and legality will remain complicated. As such, pharmacotherapy with cannabis should be considered with caution until this changes.

External Resources:
  1. The Endocannabinoid System and Parkinson Disease
  2. Medical Cannabis in Parkinson Disease: Real-Life Patients' Experience
  3. Medical cannabis as an alternative therapeutics for Parkinsons’ disease: Systematic review
  4. Marijuana Compounds: A Nonconventional Approach to Parkinson’s Disease Therapy
  5. Cannabis use in people with Parkinson’s disease and Multiple Sclerosis: A web-based investigation
  6. Pros and Cons of Medical Cannabis use by People with Chronic Brain Disorders
  7. Effects of acute cannabidiol administration on anxiety and tremors induced by a Simulated Public Speaking Test in patients with Parkinson's disease
  8. A Study of Tolerability and Efficacy of Cannabidiol on Motor Symptoms in Parkinson's Disease
  9. Cannabidiol for the treatment of psychosis in Parkinson's disease
This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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