Potential Health Benefits of Medical Marijuana: a Look at the Research

Potential Health Benefits of Medical Marijuana: A Look at the Research

This article is one in a series on medical marijuana, or cannabis. These articles are solely for the purpose of educating and informing nutrition professionals about medical marijuana. They are not an endorsement for marijuana use by Nutrition411.

Cannabis, more commonly known as marijuana, is currently legal for medical use in 28 states and the District of Columbia. At this time, however, each state has its own set of rules for use, and in many cases, limits on medical conditions that qualify for medical marijuana use. The United States (US) Drug Enforcement Administration (DEA) lists marijuana as a class 1 controlled substance, with no medical use, and a high potential for abuse and addiction. As a result, research has focused on abuse and addiction, rather than benefits, so studies on various potential health benefits are limited.

The cannabis plant is complex, with various strains, and an estimated 400 different chemical compounds. Two major compounds are instrumental in activating cannabinoid receptors located in the central nervous system and throughout the body. These receptors are part of a major body system known as the endocannabinoid system, which modulates mood, memory, appetite, and pain. The first of these cannabinoid compounds is delta-9-tetrahydrocannabinol, also known as THC, which is the well-known psychoactive compound in marijuana. The other is cannabidiol (CBD), which is not psychoactive, and modifies the effects of THC. CBD has anticonvulsant and sedative properties.

While medical marijuana cannot be touted as a cure for any diseases, it may be useful as part of a complementary or alternative medicine (CAM) regimen, especially when used in conjunction with other CAM and traditional medicines. The following are the most commonly approved medical conditions for medical marijuana and some of the research to support its use.

·  Amyotrophic lateral sclerosis (ALS): Various studies on cannabis use in patients with ALS have shown promising results. It appears that the endocannabinoid system is implicated in the pathophysiology of the disease, and animal studies suggest that cannabis may be able to modify the course of the disease, possibly by acting as an antioxidant or neuromodulator. Patients with ALS who receive cannabis as part of their treatment report improvement in symptoms of pain, spasticity, poor appetite, poor sleep, and depression. It is also beneficial for reducing saliva production, as it is often difficult for these patients to swallow. For those who respond positively to cannabis, another benefit is that is does not decrease gut motility or cause respiratory suppression, which are important considerations for ALS patients. Many patients express a preference to cannabis over prescription medications. (Bedlack 2015; Kaufman 2014)

·  Cachexia and nausea: Much of the research on the potential benefit of cannabis on cachexia and nausea has centered around cancer and HIV/AIDS. Cannabis has long been used and studied as an antiemetic agent for nausea, vomiting, and cachexia associated with chemotherapy, and in fact, FDA-approved anti-nausea medications such as dronabinol and nabilone are synthetic forms of THC. The National Comprehensive Cancer Network (http://www.nccn.org) antiemesis guidelines recommend cannabinoids among other therapies to consider as treatment for chemotherapy-induced nausea and vomiting.

Studies on cannabis as an appetite stimulant have been mixed, or of lower quality, but in a review on cannabis in cancer care, two small studies on patients with advanced cancer who received cannabis did have improved appetite and slower weight loss. Animal studies have also found cannabis intake to result in improved appetite. (Abrams & Guzman 2015)

·  Cancer: In addition to the above research on alleviating chemotherapy-associated nausea and stimulating appetite, some newer research on cannabis is suggesting that it may play a role in arresting tumor growth. Researchers have determined that THC and other cannabinoids modulate signal pathways involved in tumor growth arrest, cell death, and inhibit angiogenesis and metastasis. This tumor inhibition has been seen in cancers of the lung, thyroid, skin, uterus, breast, stomach, colon, pancreas, prostate, as well as in glioma, neuroblastoma, and leukemia/lymphoma. (Abrams 2016; Birdsall 2016)

·  Crohn’s disease: Research on Crohn’s disease and irritable bowel disease has focused on synthetic cannabinoids, which have been shown to be beneficial in managing Crohn’s symptoms. Large-scale research on cannabis and Crohn’s disease is lacking, but anecdotal evidence and patient reviews do suggest that it is helpful for controlling pain and nausea, improving appetite, and enhancing feelings of well-being. The endocannabinoid system is involved in many functions in the gastrointestinal system, including gastric acid production, nausea and vomiting, visceral sensation, gastrointestinal motility, and intestinal inflammation. While the use of cannabis has been reported to improve symptoms, it does not appear to improve the disease process. (Gerich 2015)

·  Epilepsy and seizures: Interest in medical marijuana spiked after a documentary by Dr. Sanjay Gupta, titled Weed aired on CNN in 2013. In the documentary, he highlighted a young child with a severe form of epilepsy and frequent seizures, who was dramatically helped by a very high CBD, low THC form of marijuana. Israeli researchers have studied childhood epilepsy and seizures extensively. In a retrospective study on 74 children across five epilepsy clinics, researchers determined that 89% of children who received CBD therapy had reduction in the number of seizures, and 18% had between 75%-100% improvement in seizure frequency. In addition, most patients had improvements in behavior and alertness, language, communication, motor skills, and sleep. There were some adverse reactions noted, including included somnolence, fatigue, gastrointestinal disturbances, and irritability. (Tzadok 2016)

·  HIV/AIDS: Medical marijuana is primarily used to manage pain and stimulate appetite in patients with HIV/AIDS, and study results suggest that it is beneficial for both. In a study which examined its benefits on neuropathic pain in 34 HIV patients, researchers noted that subjects had significant pain improvement when cannabis was administered by smoking. Subjects were also taking their regular analgesic medications as prescribed, but they noted more “clinically meaningful pain relief” when marijuana was added to their pain management protocol. They also reported improvements in mood disturbance, physical disability, and quality of life. (Ellis 2009).

In a review which examined any reduction in morbidity or mortality in HIV/AIDS patients who used medical marijuana or synthetic cannabis, researchers found that while many patients reported an increase in appetite, slight increase in weight gain, reduction in nausea, and improvements in performance and mood, there was no significant evidence of an effect on morbidity or mortality. (Lutge 2013)

·  Multiple sclerosis (MS): A systematic review published in the journal Neurology examined 34 studies to determine the efficacy and safety of medical marijuana in various neurologic disorders, including MS. Researchers found oral cannabis extract to be effective in reducing central pain or painful spasms, patient-reported spasticity, and possibly long-term measures of spasticity, but not for reducing bladder dysfunction or tremor (Kaufman 2014).

·  Pain: Pain reduction is one of the most common reasons for medical marijuana use, and as evidenced by many of the above-mentioned studies, it appears to help a vast majority of users manage chronic pain caused by a wide variety of conditions. Opioids have traditionally been prescribed for chronic pain management, but because of their side effects and risk of abuse and dependency, medical marijuana is being examined as a preferred long-term treatment, either by itself, or in conjunction with opioids. Interestingly, many states that have legalized medical marijuana, report state-wide reductions in opioid overdose. A study on 244 chronic pain patients examined whether there was any personal reduction in opioid use in subjects who were also treated with medical cannabis. Researchers identified a 64% reduction in opioid use and most subjects reported a better quality of life with fewer opioid-induced side effects. (Boehnke 2016).

The challenges of using medical marijuana

While much evidence appears to support the use of medical marijuana for certain health conditions, it does not come without issues and concerns about its use, even if or when it is rescheduled by the DEA. The biggest concerns for patients involve safety, quality, and dosing. Because it is a plant, and not a synthetic drug, it is susceptible to much variability in strains, growing conditions, harvesting, and processing. None of these areas are currently regulated, meaning one could potentially purchase and use plants that are tainted with pesticides or other toxins, much higher, or lower, in the active THC or CBD ingredient desired, or come from a strain which provides unexpected and undesirable effects.

Appropriate dosing is another major area of concern. Because each strain has its own active compounds, there is certain to be inconsistency in active ingredients, and it is almost impossible to determine a standardized dose for each individual or their health condition. In addition, the method of cannabis delivery into the system results in great variation in onset and effect. There is an almost immediate effect, with a shorter duration, if cannabis is vaporized by smoking or inhaling. However, with oral ingestion, onset is slower, often 1 hour, and the effect may last between 4-12 hours. At present, most practitioners who give patients a medical marijuana recommendation advise starting low and going slow to increase the dose, until the desired result is determined.

Finally, there are many who have concerns about the long-term safety of medical marijuana in the US. Several studies have found long-term users who smoke marijuana recreationally to have an increased risk of lung cancer, which appears to be independent of cigarette smoking. Another safety concern is the risk of addiction and mental health problems. Observational studies have shown that 1 in 9 long-term recreational users become addicted to marijuana. Many recreational users experience short-term effects on the brain which can impair attention, judgement, and balance, as well as impairments in thinking and learning. Longer-term and heavy users can experience negative changes in the brain chemistry, which may result in anxiety, mood disorders, or even psychosis. Much of the research on these concerns implicates the psychoactive component THC, which has been increasing in potency, in the plant sold as a recreational street drug.

References and recommended reading

Abrams DI. Integrating cannabis into clinical cancer care. Curr Oncol. 2016;23(2):S8-S14. doi:10.3747/co.23.3099.

Abrams DI, Guzman M. Cannabis in cancer care. Clin Pharmacol Ther. 2015;97(6):575-86. doi:10.1002/cpt.108.

Birdsall SM, Birdsall TC, Tims LA. The use of medical marijuana in cancer. Curr Oncol Rep. 2016;18:40. doi:10.1007/s11912-016-0530-0.

Bedlack RS, Joyce N, Carter GT, Pagononi S, Karam C. Complementary and alternative therapies in ALS. Neurol Clin. 2015; 33(4):909-936. doi:10.1016/j.ncl.2015.07.008.

Boehnke KF, Litinas E, Clauw DJ. Medical cannabis use is associated with decreased opiate medication use in a retrospective cross-sectional survey of patients with chronic pain. The Journal of Pain. 2016;17(6):739-744. doi:10.1016/j.jpain.2016.03.002.

Ellis RJ, Toperoff W, Vaida F, et al. Smoked medicinal cannabis for neuropathic pain in HIV: A randomized, crossover clinical trial. Neuropsychopharmacology. 2009;34(3):672–680. doi:10.1038/npp.2008.120.

Gerich ME, Isfort RW, Brimhall B, Siegel CA. Medical marijuana for digestive disorders: High time to prescribe. Am J Gastroenterol. 2015;110(2):208-14. doi:10.1038/ajg.2014.245.

Kaufman J, Almasy K, Boller A, Dahodwala N, Elman L, Kelley M, McCluskey L. Medical Marijuana Utilization and Perceived Therapeutic Value in Patients with ALS (P3. 014). Neurology. 2014;82(10 Supplement):P3-014. http://www.neurology.org/content/82/10_Supplement/P3.014/. Accessed August 18, 2016.

Lutge EE, Gray A, Siegfried, N. The medical use of cannabis for reducing morbidity and mortality in patients with HIV/AIDS. Cochrane Database Syst Rev. 2013;30(4):CD005175. doi:10.1002/14651858.CD005175.

Medical marijuana and the mind. Harvard Health publications website. http://www.health.harvard.edu/mind-and-mood/medical-marijuana-and-the-mind. Published April 2010. Accessed August 18, 2016.

Tzadok M, Uliel-Siboni S, Linder I, et al. CBD-enriched medical cannabis for intractable pediatric epilepsy: The current Israeli experience. Seizure. 2016;35:41-4. doi:10.1016/j.seizure.2016.01.004.

Volkow ND, Baler RD, Compton WM, Weiss SR. Adverse health effects of marijuana use. N Engl J Med. 2014;370(23):2219-27. doi:10.1056/NEJMra1402309.

Webb CW, Webb SM. Therapeutic benefits of cannabis: a patient survey. Hawaii J Med Public Health. 2014; 73(4): 109-111. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3998228/. Accessed August 18, 2016.

Contributed by Anne Danahy, MS, RDN

Review date: 11/9/16