You can find out more about NPF's National Medical Director, Dr. Michael S. Okun, by also visiting the NPF Center of Excellence, University of Florida Center for Movement Disorders & Neurorestoration. Dr. Okun is also the author of the Amazon #1 Parkinson's Best Seller 10 Secrets to a Happier Life.

There has been a recent and evolving media blitz concerning the potential use of medical marijuana (tetrahydrocannabinol, THC) in Parkinson’s disease patients.  All of the attention to marijuana has been largely a result of multiple states passing legislation to legalize and to regulate the drug; or to alternatively make it available for select medical diagnoses.  In this month’s National Parkinson Foundation What’s Hot in Parkinson’s Disease column, I will review the current state of the research into medical marijuana for Parkinson’s disease.

A recent report from the guideline development subcommittee of the American Academy of Neurology (AAN) tackled the evidence-base supporting the use of marijuana for neurological disorders.  Spasticity, central pain syndromes and bladder dysfunction (disorders not including Parkinson’s disease) seemed to be improved with marijuana use. The few available studies revealed that marijuana was not helpful in Parkinson’s disease related tremor or levodopa-induced dyskinesias. The report was careful to outline the risks and the benefits of medical marijuana, and it recommended education and counseling for anyone considering this option. The risk of serious psychopathologic effects (hallucinations, etc.) was cited to be about 1%.

In addition to the AAN report, there have been a few recent papers supporting the use of marijuana for specific Parkinson’s disease symptoms (motor, mood, quality of life, sleep), however all have suffered from methodological issues such as including small numbers of patients, and not including a proper control group.  Katerina Venderova in 2004 (Movement Disorders Journal) conducted a survey of Parkinson’s disease patients on marijuana (cannabis) and reported that “39 patients (45.9%) described mild or substantial alleviation of their PD symptoms in general, 26 (30.6%) showed improvement of rest tremor, 38 (44.7%) had improvement in bradykinesia, 32 (37.7%) had alleviation of muscle rigidity, and 12 (14.1%) had improvement of L-dopa-induced dyskinesias.  Only 4 patients in this survey (4.7%) reported that cannabis actually worsened their symptoms. Patients using cannabis for at least 3 months reported significantly more alleviation of their Parkinson’s disease symptoms in general.”  Like Venderova who conducted her survey in Prague, we have also had Parkinson’s disease patients phone us at the free 18004PDINFO National Parkinson Foundation hotline, and detail personal experiences and positive stories supportive of marijuana in Parkinson’s disease.  Collectively, the problem with all of these types of personal reports has been the lack of scientific rigor necessary to truly understand the effects of marijuana on Parkinson’s disease.

In a recent review in the New England Journal of Medicine, the National Institute on Drug Abuse (NIDA) Director Dr. Nora Volkow carefully outlined the adverse health effects of marijuana use.  In her article Dr. Volkow pointed out that marijuana, which is thought of by much of the public as a completely harmless drug, can have serious adverse effects.  She makes the following important points:

  • In the U.S. it is the most commonly used “illicit” drug
  • 12% of those 12 years or older used it in the past year
  • Smoking is the most common way people use marijuana and this can harm the lungs
  • There are available edible forms including teas and foods
  • Approximately 9% of users will become addicted, and there may be a withdrawal syndrome which can make quitting difficult for some users
  • Use in adolescence and early adulthood can contribute to worsening brain function, decreased connections between brain regions, and a decrease in IQ
  • Heavy marijuana use can rarely lead to psychosis and hallucinations
  • Marijuana can reduce cognitive and also worsen motor function
  • Your risk of a car accident doubles if you have recently smoked marijuana
  • The potency of the THC content in marijuana has increased from 3% to 12% in the last several decades making accidental overdoses, especially with food products, much more common
  • The best evidence supporting marijuana use has been shown in glaucoma, nausea, the AIDS wasting syndrome, chronic pain, multiple sclerosis, and epilepsy

Scientifically it is not crazy to think that marijuana may play some positive role in the alleviation of Parkinson’s disease symptoms.  There are cannabinoid (THC) receptors all over the brain, and these receptors seem to be concentrated in a region important to Parkinson’s disease, commonly referred to as the basal ganglia.  In fact, the globus pallidus and the substantia nigra pars reticulata, which are structures within the basal ganglia, are some of the most densely packed cannabinoid (THC) receptor areas in the human body.  It is therefore not beyond reason to think that a drug directed at these receptors might positively influence the symptoms of Parkinson’s disease.  Indeed, many drug companies remain interested in compounds influencing these receptors.

What is the bottom line for information that a person with Parkinson’s disease will need to know if considering medical marijuana.  Marijuana should never be thought of as a replacement for dopaminergic and other approved therapies for Parkinson’s disease.  Second, though most available large studies have not shown a benefit, that does not mean that there will not be a benefit.  Much more research will be needed to understand which patients, which symptoms, and how best to safely administer medical marijuana in Parkinson’s disease, especially over the long-term.  It may turn out that non-motor features such as depression, anxiety, and pain respond best, but studies are desperately needed to sort this out.  Parkinson’s disease patients living in states where marijuana has been legalized for medical use should be aware of the dangers outlined by Dr. Volkow, particularly the effects on the lungs, the dangers of driving, and accidental overdoses (particularly with food items).  Finally, states will need to develop training programs for doctors and medical teams prescribing marijuana, so that the Parkinson’s disease patient on medical marijuana can be kept as safe as possible.

Selected References for Medical Marijuana and Parkinson’s Disease:

  1. Chagas MH, Eckeli AL, Zuardi AW, Pena-Pereira MA, Sobreira-Neto MA, Sobreira ET, Camilo MR, Bergamaschi MM, Schenck CH, Hallak JE, Tumas V, Crippa JA. Cannabidiol can improve complex sleep-related behaviours associated with rapid eye movement sleep behaviour disorder in Parkinson's disease patients: a case series. J Clin Pharm Ther. 2014 May 21. doi: 10.1111/jcpt.12179. [Epub ahead of print] PubMed PMID: 24845114.
  2. Koppel BS, Brust JC, Fife T, Bronstein J, Youssof S, Gronseth G, Gloss D. Systematic review: efficacy and safety of medical marijuana in selected neurologic disorders: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2014 Apr 29;82(17):1556-63. doi: 10.1212/WNL.0000000000000363. Review. PubMed PMID: 24778283; PubMed Central PMCID: PMC4011465.
  3. Lotan I, Treves TA, Roditi Y, Djaldetti R. Cannabis (medical marijuana) treatment for motor and non-motor symptoms of Parkinson disease: an open-label observational study. Clin Neuropharmacol. 2014 Mar-Apr;37(2):41-4. doi: 10.1097/WNF.0000000000000016. PubMed PMID: 24614667.
  4. Gowran A, Noonan J, Campbell VA. The multiplicity of action of cannabinoids: implications for treating neurodegeneration. CNS Neurosci Ther. 2011 Dec;17(6):637-44. doi: 10.1111/j.1755-5949.2010.00195.x. Epub 2010 Sep 28. Review. PubMed PMID: 20875047.
  5. Iuvone T, Esposito G, De Filippis D, Scuderi C, Steardo L. Cannabidiol: a promising drug for neurodegenerative disorders? CNS Neurosci Ther. 2009 Winter;15(1):65-75. doi: 10.1111/j.1755-5949.2008.00065.x. Review. PubMed PMID: 19228180.
  6. McSherry JW. Cannabis for dyskinesia in Parkinson disease: a randomized double-blind crossover study. Neurology. 2005 Mar 22;64(6):1100; author reply 1100. PubMed PMID: 15781848.
  7. Carroll CB, Bain PG, Teare L, Liu X, Joint C, Wroath C, Parkin SG, Fox P, Wright D, Hobart J, Zajicek JP. Cannabis for dyskinesia in Parkinson disease: a randomized double-blind crossover study. Neurology. 2004 Oct 12;63(7):1245-50. PubMed PMID: 15477546.
  8. Venderová K, Růzicka E, Vorísek V, Visnovský P. Survey on cannabis use in Parkinson's disease: subjective improvement of motor symptoms. Mov Disord. 2004 Sep;19(9):1102-6. PubMed PMID: 15372606.
  9. Volkow ND, Baler RD, Compton WM, Weiss SR. Adverse health effects of marijuana use. N Engl J Med. 2014 Jun 5;370(23):2219-27. doi: 10.1056/NEJMra1402309. Review. PubMed PMID: 24897085.
Posted: 8/1/2014 9:53:55 AM by Cathy Whitlock


Browse current and archived What's Hot in PD? articles, the National Parkinson Foundation's monthly blog for people with Parkinson's written by our National Medical Director, Dr. Michael S. Okun. 

July 2014
The End for Levodopa Phobia: New Study Shows Sinemet is a Safe Initial Therapy for Treatment of Parkinson's Disease

June 2014
Is light therapy a potential treatment modality in Parkinson’s disease?

May 2014
How does the most common genetic cause of Parkinson’s Disease (LRRK2) cause Parkinson’s disease and could it be used to help develop a better therapy?

April 2014
An Update on DAT Scanning for Parkinson’s Disease Diagnosis

March 2014
Could Northera (Droxidopa) Be an Alternative Treatment for Low Blood Pressure and Passing Out Symptoms?

February 2014
The Dream of a Pill Free Existence and the Continuous Dopaminergic Pump for the Treatment of Parkinson's Disease

January 2014
Should I take Inosine to Raise my Uric Acid Levels and Treat my Parkinson’s Disease?

December 2013
Could Fungus and Mold be an Important Contributor to Parkinson’s Disease?

November 2013
Pimavanserin and the Hope for a Better Drug for Hallucinations and Psychosis in Parkinson’s Disease

October 2013
Halting of the Creatine Study

September 2013
The Importance of Identifying and Treating Caregiver Strain

August 2013
Putting Parkinson’s Disease Information into the Palm of Your Hand: Parkinson’s Enters the Smartphon

July 2013
What Parkinson’s Disease Patients Need to Know about H. Pylori Gastrointestinal Infections

June 2013
A2A Receptor Antagonists and Parkinson’s Disease Treatment

May 2013
Another Setback for Trophic Factor Treatment in Parkinson's Disease

April 2013
IPX066 and What Patients Really Want in New Carbidopa/Levodopa (Sinemet) Formulations

March 2013
The Weather Forecast for Parkinson’s Disease Calls for Worldwide Economic Storm

February 2013
Defeating the Barriers to Implementing Exercise Regimens in Parkinson’s Disease Patients

January 2013
When should you start medication therapy for Parkinson’s disease?

December 2012
Neurologist Care Reduces Hospitalizations in Parkinson's Disease

November 2012
A Victory in Court for Parkinson's Disease Patients who Require Ongoing Rehabilitative Therapies

October 2012
Given the recent FDA announcement about Mirapex (pramipexole), should I be worried about dopamine agonists?

September 2012
What about the new Parkinson’s Disease Vaccine? What should I know?

August 2012
Caffeine as a Potential Treatment for Parkinson’s Disease

July 2012
Time to Consider GPi DBS for Parkinson’s Disease: A Shift in the Practice of Patient Selection for DBS

June 2012
A New Treatment for Parkinson’s Disease-Related Constipation

May 2012
Too Many Pills: Improving Delivery Systems for Parkinson’s Disease Drugs

April 2012
Measuring Quality and Assessing Depression in Parkinson's Disease

March 2012
Watch out for Unexpected Obstacles if You Use a Cueing Strategy to Break Freezing of Gait in Parkinson’s Disease

February 2012
Pill Color, Generic Medications and Insurance Issues: Important Medication-Related Tips for the Parkinson’s Disease Patient

January 2012
Are Blood Tests for Parkinson’s Disease on the Horizon?

December 2011
Placing Stem Cells in Animal Models of Parkinson’s Disease: Another Important Step

November 2011
Important News for the Parkinson’s Disease Community: More Evidence that Sinemet and Madopar are Not Toxic and do Not Accelerate Disease Progression

October 2011
The Case for All Parkinson’s Disease Patients to be Co-managed by a Primary Care-Neurologist Team

September 2011
Scientists say Research on Brain Proteins Involved in Parkinson’s Disease is “Shaping” Up

August 2011
Who Actually Takes Care of Most of the Parkinson’s Patients Worldwide: The Need for Education and the Parkinson’s Toolkit

July 2011
If you are Dizzy or Passing Out, it could be Your Parkinson’s Disease or Parkinson’s Disease Medications

June 2011
How Will Group Visits for Parkinson’s Disease Fit into the Future of Parkinson’s Disease Care?

May 2011
Why Patients Should be Wary of Chelation Therapy for Parkinson’s Disease

April 2011
Opening the Door to Gene Therapy in Parkinson’s Disease: The Need for Refinement of the Technology and Approach

March 2011
Does it Matter if I Can’t Get Brand Sinemet?

February 2011
Should I get a DaTscan or PET scan to confirm my diagnosis of Parkinson’s disease?

January 2011
A Critical Reappraisal of the Worst Drugs in Parkinson’s Disease

December 2010
Environmental Risks for PD: Manganese, Welding, Mining, and Parkinsonism

November 2010
Calling for the FDA to Revise the Eight Sinemet a Day Rule

October 2010
Dry Cleaning Solvents and Potential Environmental Risks for Developing Parkinson’s Disease

September 2010
Maintaining the Balance: Why Parkinson’s Disease Patients Need to Understand Drug Recalls, Withdrawals, and Safety Alerts

August 2010
Shining a Light on Parkinson’s Disease: Optogenetics Has a Bright Future in Research

July 2010
Poor Medication Management of Parkinson's Disease During Hospital Admissions: Patients and Families Can Improve Their Hospital-Based Management

June 2010
Why Are Patches and Continuous Release Technology a Big Deal to Parkinson's?

May 2010
Is the PD SURG Trial Another Surge Forward for DBS Therapy?

April 2010
Cycling in PD in Those Who Can’t Walk: Is it Possible?

March 2010
New iPS Stem Cells for PD: What Does it Mean?

February 2010
Time for Comprehensive Care Networks for PD

January 2010
Is Parkinson's Disease a Prion Disease?

December 2009
Parkinson's Disease Linked to Gaucher's Disease

November 2009
Brain Cells Keep Time Stamps: Implications for Parkinson's Disease Therapies

October 2009
Is it Safe to Have an MRI with a DBS in Place?

September 2009
Take Care of Your Bones as They Are Affected in Parkinson's Disease (Even in Men)

August 2009
Is it Time to Start Paying Attention to Pain Symptoms in Parkinson's Disease Patients?

July 2009
Glutathione Fails to Demonstrate Significant Improvement in PD Symptoms

June 2009
Keeping an Eye on Trials Important to the Parkinson's Disease Patient

May 2009
Increased Risk of Melanoma in Parkinson's Disease

April 2009
Finally a DBS Expert Consensus Statement Aimed at Their True Customers: The Patients

March 2009
Pesticides and Environmental Exposure in Parkinson's disease: Should We Stay Away From the Stink Truck?

February 2009
Is Exercise Effective Treatment and Protection Against PD?

January 2009
Why are Transplant Trials Struggling to Succeed in the Treatment of PD?

December 2008
Are Monoamine Oxidase Inhibitors Disease Modifying or Neuroprotective in PD?

November 2008
Update on Gene Therapy for Parkinson's Disease

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Each month, we will feature a new column by NPF's National Medical Director, Dr. Michael Okun, on the latest developments in Parkinson's disease research. Read the latest "What's Hot in PD?" below.

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