Parkinson’s disease (PD)

Parkinson’s disease (PD) is a progressive neurodegenerative disease that causes muscular rigidity and stiffness, tremors, cramps, and slow, imprecise movement. PD affects primarily middle-aged and older adults, and is associated with a deficiency of the neurotransmitter dopamine, and degeneration of the brain’s basal ganglia.

A recent study by the Parkinson’s Foundation estimates that there is an annual incidence rate of PD in 90,000 people aged 65 or older. Parkinson’s is a growing health concern in the U.S. and other parts of the world due to aging populations.

Although treatments exist, many medications can cause negative side effects when used in the long term. These can include nausea, dizziness, hallucinations, and bowel and bladder issues. Behavioral changes may also occur, including compulsive behaviors like gambling or overeating.

Medical cannabis and cannabinoids like THC and CBD may help reduce tremors, boost dopamine production, aid sleep, and provide pain relief.

Parkinson’s disease causes

Parkinson’s disease is caused by the degeneration of dopamine-producing neurons in the substantia nigra, a part of the brain responsible for motor control. Dopamine deficiency leads to the characteristic symptoms of PD. While the exact cause is unknown, contributing factors include:

• Genetic predispositions
• Environmental exposures (e.g., pesticides)
• Traumatic brain injuries (TBIs)
• Oxidative stress and inflammation

Parkinson’s disease symptoms & health effects

Motor symptoms

• Tremors: Involuntary shaking of body parts
• Muscular rigidity: Stiffness and reduced flexibility
• Bradykinesia: Slowness of movement
• Postural instability: Issues with balance and coordination

Non-motor symptoms

• Dementia
• Depression and anxiety
• Loss of smell (anosmia)
• Memory problems
• Pain and fatigue
• Sleep disturbances

Parkinson’s disease diagnosis

Diagnosing Parkinson’s disease involves a combination of methods:

• Medical history and symptom evaluation: Identifying characteristic motor and non-motor symptoms
• Neurological examination: Assessing movement, reflexes, and coordination
• Imaging tests: Such as MRI or PET scans to rule out other conditions
• Response to Levodopa: Improvement with dopamine precursor medications may confirm diagnosis

Parkinson’s disease prognosis

Parkinson’s disease is a progressive condition, and its severity varies among individuals. While it is not curable, treatments can manage symptoms effectively for many years. Prognosis depends on factors like age at diagnosis, severity of symptoms, and response to therapies. Common challenges include worsening mobility, cognitive decline, and increased dependency on caregivers over time.

Those with Parkinson’s disease tend to have a normal or near normal life expectancy, but a number of factors may shorten it. These include age at diagnosis, the severity of symptoms, experiencing any falls or infections such as flu, and gender, with men being more likely to die earlier from PD than women.

Parkinson’s disease treatments

There are several medications designed to boost dopamine production and reduce Parkinson’s symptoms. Physical and other therapies are also often implemented to manage movement, mood, and speech.

First-line treatments

1. Levodopa and carbidopa (L-DOPA, Sinemet, Pharmacopa, Atamet): Boost dopamine levels to improve motor symptoms
2. Dopamine agonists: Mimic dopamine effects in the brain
3. MAO-B inhibitors: Slow dopamine breakdown

Other treatments

• Anticholinergics: Reduce tremors and stiffness
• Amantadine: May help with dyskinesia (involuntary movements)
• Antipsychotics: Manage psychiatric symptoms, but can worsen motor issues

Adjunctive therapy & alternative treatments

• Physiotherapy and occupational therapy (OT): Aid mobility and daily functioning
• Speech therapy: Addresses speech and swallowing issues
• Deep brain stimulation (DBS): Surgically implanted electrodes regulate brain activity

Cannabis for Parkinson’s disease

Emerging evidence suggests that medical cannabis may help manage symptoms of Parkinson’s disease, including tremors, muscle rigidity, and sleep disturbances. Cannabinoids like CBD and THC, along with specific terpenes and flavonoids, may offer neuroprotective and symptomatic relief. However, while promising, cannabis’ role in Parkinson’s treatment is not yet fully established, and more high-quality clinical trials are needed.

Patients considering medical cannabis should consult healthcare professionals to determine the most suitable cannabinoid profiles and dosing strategies.

Potential benefits

• Dopamine modulation: THC and CBD may increase dopamine production, alleviating motor symptoms including tremors and rigidity
• Muscle relaxation: Cannabis may reduce stiffness and tremors
• Neuroprotection: Cannabinoids like CBD and CBG may protect against neural degeneration
• Pain relief: THC offers analgesic effects to reduce pain sensitivity
• Sleep improvement: Cannabis may address insomnia and other sleep disorders

Cannabinoid profiles

• • CBD: Anti-inflammatory, neuroprotective, and anti-anxiety (anxiolytic) properties
  • THC: Sedative, pain-relieving, and dopamine-boosting effects

• CBN: Sedative properties that can manage insomnia

• CBG: Neuroprotective and anti-inflammatory properties

Terpenes and flavonoids

• Limonene:Uplifting effects
• Pinene:Enhances focus and counteracts THC’s cognitive side effects.
• Beta-caryophyllene, linalool, and myrcene: Anti-inflammatory, analgesic, and sedative properties

Dosing and administration

• Ingestion, e.g. edibles: Long-lasting effects
• Sublingual, e.g. tinctures: Combines faster onset with prolonged effects
• Vaporization and inhalers: Rapid symptom relief

Safety considerations

• THC may worsen cognitive symptoms like memory loss and confusion, and can blunt dopamine receptors with long-term use
• Efficacy varies between individuals; cautious dosing and monitoring is crucial

Additional information for patients

Scientific evidence and anecdotal reports

Key findings from studies

• “Reduction of pain and muscle cramps was reported by more than 40% of cannabis users. Stiffness and tremors improved in more than 20%.”
  Source: Yenilmez, F. et al., Journal of Parkinson’s Disease, 2021
• “Although observational studies show subjective symptom alleviation, there is insufficient evidence to fully integrate cannabis into clinical practice for motor symptom treatment.”
  Source: Thanabalasingam, S. et al., Therapeutic Advances in Neurological Disorders, 2021

Charities and organizations that campaign for awareness and treatment for Parkinson’s disease include:

• American Parkinson Disease Association (APDA)
• The Michael J. Fox Foundation for Parkinson’s Research
• Parkinson’s Foundation

Parkinson’s disease FAQs

What are the different stages of Parkinson’s disease (PD)?

There are four stages in Parkinson’s disease, often numbered 1, 2, 3, or 4, with stage 4 being the most severe.

Parkinson’s stage 1 (early stage): Symptoms are mild and only affect one side of the body. Patients may not notice the changes and don’t usually require medication.

Parkinson’s stage 2 (middle stage): Symptoms become more severe, especially with balance and gait. Patients may need rehabilitation or assistive devices to prevent falls.

Parkinson’s stage 3 (advanced stage): Patients experience a loss of physical independence. They may need a wheelchair to get around and a caregiver for most tasks.

Parkinson’s stage 4 (palliative stage): This stage focuses on relieving symptoms, pain, and stress.

At what age does dementia start in those with Parkinson’s, and how many develop dementia?

Around 74% of those with Parkinson’s develop dementia after 20 years of disease duration. Movement-related symptoms tend to develop first, usually occurring between the ages of 50 and 85. Dementia can set in 10 years after movement-related symptoms develop, but this is not always the case.

What are the signs that Parkinson’s disease is getting worse?

Common signs of Parkinson’s disease progressing and going into a new stage include:

• Insomnia and changes in sleep patterns
• Increased difficulties with speech and swallowing
• Increased tremors and stiffness
• Memory problems
• Slower movements
• Mood changes, including anxiety and depression

Resources

• The effects of Δ9-tetrahydrocannabinol on the dopamine system: https://pmc.ncbi.nlm.nih.gov/articles/PMC5123717/
• Parkinson Disease: https://www.ncbi.nlm.nih.gov/books/NBK470193/
• Cannabinoids in Treating Parkinson’s Disease Symptoms: A Systematic Review of Clinical Studies: https://pubmed.ncbi.nlm.nih.gov/37253174/
• The Neuroprotective Effects of Cannabis-Derived Phytocannabinoids and Resveratrol in Parkinson’s Disease: A Systematic Literature Review of Pre-Clinical Studies: https://pmc.ncbi.nlm.nih.gov/articles/PMC8699487/
• A Brain on Cannabinoids: The Role of Dopamine Release in Reward Seeking: https://pmc.ncbi.nlm.nih.gov/articles/PMC3405830/
• Long-Term Dementia Risk in Parkinson’s Disease: https://pmc.ncbi.nlm.nih.gov/articles/PMC11318527/

Incidence of Parkinson disease in North America: https://www.nature.com/articles/s41531-022-00410-y

Please note: the information in this article does not constitute medical advice

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