Eyes Wide Shut: Looking at Medical Marijuana's Effects

There’s been a lot of press recently about the medicinal effects of marijuana.  For example, one state medical marijuana association, an advocate for medical cannabis, reports that marijuana can cure and relieve hundreds of primary medical problems.  Below is just a partial list of what this association stated marijuana can treat or improve:

• Asthma
• Glaucoma
• Tumors
• Nausea
• Epilepsy
• Multiple sclerosis
• Back pain
• Muscle spasms
• Infections
• Arthritis
• Herpes
• Cystic fibrosis
• Rheumatism
• Lung function
• Sleep problems
• Emphysema
• Stress
• Migraine headaches
• Increase appetite
• Decrease saliva
• AIDS
• Depression
• Meditation
• Concentration
• Consciousness-raising
• Promoting well-being
• Self-assertiveness
• Dementia
• Senility
• Alzheimer’s
• Greater life expectancy

Does this seem too good to be true?  I certainly thought so.  That’s why I wondered how much of what we hear today about marijuana’s medical uses is based on sound science versus biased or unfounded information coming from the marijuana industry, folklore or a comment made by friend who heard it from his mother who overheard it from someone in a checkout line at a grocery store.

My point is that many of the reports about marijuana’s effectiveness in treating an increasingly growing list of human maladies appears based in part on anecdote, hearsay and advertising rather than actual data.  The decision to use marijuana to treat a mental or physical condition is a serious one, and as good consumers we should not assume all medical marijuana claims are accurate or its use harmless.

Marijuana Plant as Medicine

Keep in mind that although marijuana has been used therapeutically for centuries, today’s use of medical marijuana in its various plant and extract forms, whether smokable, edible, extract or topical, is not controlled for purity, dosage, side-effects, safety or efficacy like prescription, or even over-the-counter drugs.  This reality is reflected by the fact that the US Food and Drug Administration (FDA) has not approved the marijuana plant as medicine.

To illustrate, smoking pot to alleviate pain is like smoking willow tree bark because it contains salicylic acid, the main active ingredient in aspirin.  Salicylic acid has been found an effective medicine, and today is used throughout the world to reduce pain, fever and inflammation in pill, powder and liquid forms.

We no longer smoke or eat willow bark like early Native Americans, or the ancient Greeks, Chinese and Europeans.  Nor do we smoke opium or tobacco for their once perceived health benefits.  Yet today, pro-marijuana groups and some supporters promote smoking and/or eating the crude marijuana plant and its extracts for medicinal purposes.    

State Medical Marijuana Laws

Currently there are 28 states, plus the District of Columbia, Guam and Puerto Rico, that have approved legislation permitting the use of marijuana for medical uses.  To make safe decisions for ourselves and our families, we all need to be informed about the medical marijuana laws in our state and therapeutic claims attributed to marijuana.

Laws differ from state to state regarding whether and which medical conditions marijuana can be used to treat.  Medical approval to use marijuana usually comes in the form of a “referral” or “recommendation,” because federal law prohibits prescriptions for marijuana as it is still listed a Schedule I drug.

An Institute of Medicine report in 1999 titled Marijuana and Medicine: Assessing the Scientific Base found scientific data indicated a potential therapeutic effect from marijuana drugs, but that smoking marijuana is a crude delivery system that also supplies harmful substances.  In addition, the psychological effects of marijuana, such as euphoria, sedation and anxiety reduction, can influence and complicate the interpretation of the drug’s effects.

According to the National Conference of State Legislatures, studies have shown that marijuana has potential therapeutic value for pain relief, control of nausea and vomiting, and appetite stimulation, as well as more recently for relieving some symptoms of HIV/AIDS, cancer, glaucoma and multiple sclerosis.  http://www.ncsl.org/research/health/state-medical-marijuana-laws.aspx 

Marijuana and Cannabinoids

There are over 100 cannabinoids found in the marijuana plant, the active ingredients in the cannabis plant.  Of these, there are two that have been identified as having some potential for medical uses.  These include THC and CBD.

THC, or delta-9-tetrahydrocannabinol, is the most common cannabinoid in marijuana and the chemical that is responsible for the “high” when using cannabis.  THC has been found to be useful in increasing appetite and reducing nausea.  According to the National Institute on Drug Abuse (NIDA), it may also decrease pain, inflammation and problems with muscle control.

The other cannabinoid is CBD, or cannabidiol, which does not have the intoxicating effects that THC does, but has been identified more recently as having medicinal potential.  NIDA states that CBD may be useful in reducing pain and inflammation, controlling epileptic seizures, and treating mental health problems and addictions.

In addition, recent animal studies show marijuana extracts can kill and reduce the size of cancer cells.  Other studies are examining marijuana or its extracts effects on HIV/AIDS, multiple sclerosis and Alzheimer’s disease.

There are currently two FDA approved medicines containing THC in pill form.  These include dronabinol and nabilone.  Both medicines are used to treat nausea caused by chemotherapy used in cancer treatments, and to increase appetite in patients with wasting syndrome caused by HIV/AIDS.

Other countries, like Canada and the United Kingdom, have also approved the drug nabiximols which contains THC and CBD in a mouth spray to treat muscle control problems caused by multiple sclerosis.  Another drug, Epidiolex, contains CBD in liquid form to treat certain types of childhood epilepsy.

Reviews of Medical Marijuana Effects

To help synthesize clinical research evaluating the efficacy of marijuana to treat various medical conditions, research reviews published in the past few years are presented below.

One of two reviews of medical marijuana for treating medical problems was published in 2015 in the Journal of the American Medical Association (JAMA).  Studies reviewed showed that there was high-quality evidence for the use of marijuana or cannabinoids to treat chronic pain, neuropathic pain, and spasticity due to multiple sclerosis.  However, many of the medical problems claimed to be helped by marijuana use were not supported, including sleep disorders, Tourette syndrome, anxiety disorders, depression and psychosis, and eye pressure resulting from glaucoma.

http://jamanetwork.com/journals/jama/article-abstract/2338266

Another review of cannabinoids for use in medicine published in the same issue of JAMA found that there was moderate-quality evidence to support the use of cannabinoids for the treatment of chronic pain and spasticity, and low-quality evidence that cannabinoids improved nausea and vomiting due to chemotherapy, weight gain in HIV infection, sleep disorders, and Tourette syndrome.  In addition, cannabinoids were associated with an increased risk of short-term adverse events, including physical weakness or lack of energy, balance problems, confusion, dizziness, disorientation, diarrhea, euphoria, drowsiness, dry mouth, fatigue, hallucination, nausea, drowsiness and vomiting. http://jamanetwork.com/journals/jama/fullarticle/2338251

One of two systematic reviews of research examining cannabinoids in the treatment of chronic, non-cancer pain was published in 2015 in the Journal of Neuroimmune Pharmacology.  Study authors concluded that currently available cannabinoids are safe, modestly effective analgesics that provide a reasonable therapeutic option in the management of chronic non-cancer pain. http://link.springer.com/article/10.1007/s11481-015-9600-6

Another review of the effectiveness of cannabinoids in the management of non-cancerous neuropathic pain was published in 2015 in the Journal of Oral & Facial Pain and Headache.  The authors concluded that cannabis-based medicinal extracts used in different populations of chronic non-malignant neuropathic pain patients may provide effective analgesia in conditions that are resistant to other treatments. https://www.researchgate.net/profile/Greg_Goddard2/publication/272406849_The_Effectiveness_of_Cannabinoids_in_the_Management_of_Chronic_Nonmalignant_Neuropathic_Pain_A_Systematic_Review/links/565e6aa308aeafc2aac8fa9c.pdf

One of two reviews of research on the use of cannabis for mental health therapeutic purposes was published in 2016 in Clinical Psychology Review.  Results of the research reviewed indicated preliminary evidence that marijuana has potential for treating PTSD, and as an exit drug to reduce the severity of other substance use disorders like opioid pain medication, but that it may be problematic among individuals with psychotic disorders.  http://www.sciencedirect.com/science/article/pii/S0272735816300939

By contrast, another systematic review of research medical marijuana in psychiatric indications published in 2016 in the Journal of Clinical Psychiatry found that the strength of evidence for the use of marijuana for Tourette’s disorder, PTSD, and Alzheimer’s disease was very low.

http://www.psychiatrist.com/jcp/article/Pages/2016/v77n08/v77n0818.aspx

A review published in 2015 in the Journal of Developmental Behavioral Pediatrics examined research on medical marijuana for treating developmental and behavioral disorders in children and adolescents, including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).  The authors concluded that cannabis cannot be recommended for treating pediatric developmental behavioral conditions because of the lack of evidence, and the long-term known risks associated with regular cannabis use among youth.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4318349/

In a 2015 editorial in JAMA, the question was raised whether the cart is before the horse in terms of state approved medical uses of marijuana without first having solid science supporting its specific efficacy.  The editorial authors state that recent research reviews provided some evidence to support marijuana use for nausea and vomiting related to chemotherapy, specific pain syndromes, and spasticity from multiple sclerosis, but that evidence supporting most other indications approved by state laws is of poor quality.  http://jamanetwork.com/journals/jama/article-abstract/2338230

Potential Risks from Medical Marijuana

In addition to the lack of high quality data supporting the efficacy of specific cannabinoid compounds for treating various human diseases and symptoms, there are unanswered questions about marijuana’s safety, particularly given the wide variations and lack of quality control in terms of medical marijuana’s potency, dosing, purity, tolerability, side-effects, drug interactions, and efficacy in relation to other pharmacological treatments.

A decision to use medical marijuana must include weighing the current evidence supporting its efficacy against potential marijuana risks, including acute over-intoxication and dangers associated with combining marijuana with alcohol and other drugs, as well as chronic use risks including psychosis, highway accidents, problems with memory, attention, decision-making and IQ, addiction, and access by and harm to youth.

Concerning the later risk, there has been a pattern in which states first approve the use of medical marijuana and later permit recreational cannabis use for adults.  Legalizing recreational marijuana consumption can increase youth access to marijuana products and beliefs that marijuana is harmless, inflate norms regarding use and acceptability, and eventually increase the prevalence of youth marijuana use and cannabis use disorders.

Conclusions

In conclusion, the key points described in this article are:

1) there are reports of marijuana’s medical effects that far surpass any sound evidence supporting its efficacy or safety;

2) marijuana in plant and extract forms are being smoked and consumed today as crude medicines like they have been for centuries beforehand, although the FDA has not approved the marijuana plant as medicine;

3) laws dictating which, if any, medical conditions marijuana can be used to treat vary across states, and between state and federal jurisdictions;

4) the two primary cannabinoids that have been identified as having medical uses are THC and CBD;

5) the strongest evidence appears to support marijuana’s efficacy for treating chronic pain, neuropathic pain, and spasticity due to multiple sclerosis;

6) some evidence also exists for marijuana’s potential to improve nausea and vomiting due to chemotherapy, increase weight gain in HIV infection, reduce the severity of other substance use disorders, and improve certain types of childhood epilepsy; and

7) any decision to use medical marijuana, particularly in its plant and extract forms, must be weighed against the potential acute and chronic health and safety risks, and potential secondary harm to youth through increased access and pro-marijuana use beliefs and norms.

Each state that permits medical marijuana use determines by law which medical conditions can be treated with the use of cannabis.  These decisions are fluid and depend in part upon the relationship between federal drug laws which don’t allow the use of marijuana for medical or recreational purposes.  In addition, state laws and medical practice will change as scientific knowledge of the potential efficacy and safety of marijuana and its specific cannabinoids increases.

Further scientific study will continue to shed light on what medical conditions might be improved with which cannabinoids, as well as at what doses are optimal and what side effects and contraindications can be expected.  The advancement of our scientific knowledge of the full potential of marijuana for treating medical conditions will take time.

One day the smoking of marijuana and use of crude cannabis extracts will all but be eliminated from medical practice in lieu of carefully dosed, pure cannabinoids in pill, liquid, spray or patch formats like other medicines, thereby reducing risks associated with current methods of marijuana delivery.

In the interim, it would be wise for anyone thinking of using marijuana for medical purposes consider the Latin phrase “caveat emptor,” or let the buyer beware.  Consumers should carefully weigh the potential benefits against the risks posed by using current forms of marijuana to health, safety and the potential for addiction, as well as secondary negative effects on youth.

Finally, special caution should be practiced by anyone considering using marijuana to self-medicate a health or life problem without physician approval and consultation.  Like misusing any drug, medical marijuana can cause serious pain and suffering to oneself and one’s family if not used with your eyes wide open.