Christopher J. Froehlich, Catherine J. Randall Research Scholar, University of Alabama Alan Blum, MD, Center for the Study of Tobacco and Society, University of Alabama
Marijuana has been used both medicinally and as an intoxicant for thousands of years, notably in China. Europe and the Americas have mostly been exposed to marijuana as a medicine for about 200 years. Marijuana has progressed from an herbal medicine to a notorious illicit drug to a popular recreational drug and an alternative medicine. This change in public perception in recent years is the result of anecdotal reports on social media of its benefits. Because it is difficult for medical researchers to obtain marijuana for studies, there are insufficient data to prove or disprove many of these claims.1 One result is that medical approval of marijuana is left to state legislatures, who are “essentially legalizing recreational marijuana but forcing physicians to act as gatekeepers for those who wish to obtain it.”2
How Is Marijuana Used?
Marijuana as a drug (i.e. a substance intended to affect the structure or function of the body) consists of about 500 chemical compounds. The primary components are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).3 THC is responsible for the high that users seek.4
Marijuana is the most popular illicit drug in the United States. 35 million people are regular users (at least once a month).5,6
Around 90% of adult users describe their primary cannabis use as recreational (i.e. as a diversion).7
36% of users report mixed medical and recreational marijuana usage.7
Users may consume marijuana in a variety of ways, such as cigarettes (joints), cigars (blunts), water pipes (bongs), vaporizers, or orally in the form of gummy bears, brownies, or other edibles.5,8
Marijuana is made from the flowering tops and fruits (buds, pictured below) from female cannabis plants.9 Although the most recognizable part of the plant is its leaves, these are not smoked.
Chinese compendium of drugs (the oldest in the world) recommends marijuana to treat various conditions.²⁵
Dr. William O’Shaughnessy becomes one of the first Western doctors to report marijuana’s treatment of vomiting and diarrhea caused by cholera.²⁵
First American conference on clinical use of marijuana. Physicians reported success in treating chronic cough, pain, and other conditions.²⁵
American pharmaceutical companies manufacture standardized extracts of marijuana.²⁵
Congress passes Marijuana Tax Act, restricting sales and prescription to combat crime and mental illness.²⁵
Marijuana was removed from the United States Pharmacopoeia (USP) for being dangerous and addicting drug.²⁶
Controlled Substances Act passed. Marijuana is classified as a Schedule 1 drug, considered to have a high risk of abuse and no accepted medical benefit.
California becomes first state to legalize medical marijuana.
Colorado becomes the first state to legalize recreational marijuana.
FDA approves first purified drug derived from cannabis.²⁶ Other previous drugs were synthetic.
Marijuana can help cure cancer: Although micromolar concentrations of THC have been found to kill tumor cells, the nanomolar concentrations of THC that are more likely to be the result of recreational or medical use have been found to induce proliferation of cancer cells.10
Dabbing is safe: “Dabbing” involves the vaporization of concentrated butane hash oil (BHO), in which butane is used to extract THC from marijuana to produce an orange wax.11 THC concentrations in BHO vary wildly, from 4 to 30 times the concentrations found in the cannabis flower.12,13 This elevated concentration of THC in dabs can cause severe neurotoxicity and cardiotoxicity.14
Marijuana is not related to the development of psychotic disorders: THC produces symptoms that resemble those of psychotic disorders.15 Positive symptoms (those added onto normal behavior) include suspiciousness, paranoid and grandiose delusions, conceptual disorganization, fragmented thinking, and perceptual alterations.16 Negative symptoms (those that take away from normal behavior) include “blunted affect, reduced rapport, lack of spontaneity, psychomotor retardation, and emotional withdrawal.”15
There exists an association between marijuana use and psychosis that meets many but not all of the standard criteria for causality.16 It may be that marijuana use precedes the development of psychosis, or people who will develop psychosis are more likely to use marijuana, or both. Regardless of the exact sequence, there are similarities between this association and those between smoking and lung cancer, or between high sodium intake and hypertension.16
Marijuana can be useful for treating multiple sclerosis (MS): However, there is no way to measure spasticity, and any improvement is self reported.17 Marijuana also impairs balance and posture, exacerbating these symptoms of MS.18 It could be possible for patients to grow accustomed to this impairment and learn to counteract it.17
Marijuana is safe during pregnancy: Marijuana use during pregnancy is associated with an increased risk of preterm birth.19
Dispensaries responsibly recommend marijuana to their patrons: In a statewide cross-sectional study, 69% of Colorado dispensaries recommended cannabis to treat the morning sickness of a caller claiming to be 8 weeks pregnant. Dispensaries with medical licenses were more likely to recommend cannabis, and 36% of all dispensaries stated cannabis use during pregnancy was safe.20
Marijuana is safe to use with other medications: Cannabis may have drug interactions that are still unknown.19 There has been at least one probable interaction between cannabis and warfarin, resulting in gastrointestinal bleeding, nosebleeds, and increased bruising during the period of cannabis use.21
Marijuana is an effective treatment for glaucoma: Many states in which marijuana is approved for medical use permit it to be prescribed for glaucoma, but it is an ineffective treatment. Marijuana does lower the intraocular pressure that causes damage, but it only does so for 3-4 hours at a time. Constant treatment is required to be effective.22
Potential Medical Benefits
Manages Multiple Symptoms: Although marijuana is a less effective treatment of individual symptoms such as nausea, diminished appetite, and pain than other medications, it does treat these symptoms simultaneously, potentially reducing the number of medications a patient must take.23
Fast Antiemetic Effects: The rapid uptake of inhaled THC may prevent vomiting better than a pill, since patients may not be able to keep a pill down long enough for it to be effective.23
Ability to Self Titrate: Inhalation of THC also enables patients to use the minimum dosage required to manage their symptoms, reducing the risk of undesirable side effects.23
Epilepsy Treatment: CBD has the potential to dramatically reduce the number of seizures in various forms of epilepsy. After using Epidiolex, the first FDA approved medication derived from cannabis extracts, for 12 weeks, the median number of seizures decreased from 144 seizures per two weeks to 52 seizures per two weeks.24
Research on the medical use of marijuana remains largely inconclusive because of the inherent obstacles to studying an illegal substance. Although proof of beneficial uses of marijuana may well emerge, currently the risks outweigh the benefits.
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National Institute on Drug Abuse [Internet]. The Institute; Marijuana; 2019 Sep 20 [cited 2019 Dec 6]. Available from: https://www.drugabuse.gov/publications/research-reports/marijuana.
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Marist College Institute for Public Opinion. Yahoo News/Marist Poll: Weed & the American family. Poughkeepsie, NY: The Institute; 2017 Apr 17.
Committee on the Health Effects of Marijuana. The health effects of cannabis and cannabinoids: the current state of evidence and recommendations for research. Washington, DC: The National Academies of Sciences, Engineering and Medicine; 2017 Jan 12. Available from: https://doi.org/10.17226/24625.
Timberlake DS. A comparison of drug use and dependence between blunt smokers and other cannabis users. Subst Use Misuse. 2009 Jul 3;44(3):401-15. Available from: DOI:10.1080/10826080802347651.
Hart S, Fischer OM, Ullrich A. Cannabinoids induce cancer cell proliferation via tumor necrosis factor α-converting enzyme (TACE/ADAM17)-mediated transactivation of the epidermal growth factor receptor; Cancer Res. 2004 Mar 15; 64(6):1943-50. Available from: DOI: 10.1158/0008-5472.CAN-03-3720.
Stogner JM, Miller BL. The dabbing dilemma: a call for research on butane hash oil and other alternate forms of cannabis use. Substance Abuse. 2015 Nov 20; 36(4):393-5, Available from: DOI: 10.1080/08897077.2015.1071724.
Mehmedic Z, Chandra S, Slade D, et al. Potency trends of Δ9‐THC and other cannabinoids in confiscated cannabis preparations from 1993 to 2008*. Journal of Forensic Sciences. 2010 Sep 1;55(5):1209-17. Available from: DOI:10.1111/j.1556-4029.2010.01441.x.
Rickner SS, Cao D, Kleinschmidt K, et al. A little “dab” will do ya’ in: a case report of neuro-and cardiotoxicity following use of cannabis concentrates, Clinical Toxicology. 2017 Jun 23;55(9):1011-13. Available from: DOI: 10.1080/15563650.2017.1334914.
D’Souza D, Perry E, MacDougall L, et al.The psychotomimetic effects of intravenous delta-9-tetrahydrocannabinol in healthy individuals: implications for psychosis. Neuropsychopharmacol. 2004 Jun 2;29(8):1558–72. Available from: doi:10.1038/sj.npp.1300496.
Radhakrishnan R, Wilkinson ST, D’Souza DC. Gone to pot – a review of the association between cannabis and psychosis. Front Psychiatry. 2014 May 22;5:54. Available from: DOI:10.3389/fpsyt.2014.00054.
Mack A, Joy J. Marijuana as medicine? The science beyond the controversy. Washington, DC: National Academies Press; 2000.
Greenberg HS, Werness SA, Pugh JE, et al. Short-term effects of smoking marijuana on balance in patients with multiple sclerosis and normal volunteers. Clinical Pharmacology and Therapeutics. 1994 Mar;55(3):324-8. Available from: https://doi.org/10.1038/clpt.1994.33.
Corsi DJ, Walsh L, Weiss D, et al. Association between self-reported prenatal cannabis use and maternal, perinatal, and neonatal outcomes. JAMA.2019 Jun 18;322(2):145–52. Available from: DOI:10.1001/jama.2019.8734.
Dickson B, Mansfield C, Guiahi M, et al. Recommendations from cannabis dispensaries about first-trimester cannabis use. Obstet Gynecol. 2018 Jun;131(6):1031–8. Available from: DOI:10.1097/AOG.0000000000002619.
Yamreudeewong W, Wong HK, Brausch LM, et al. Probable interaction between warfarin and marijuana smoking. Ann Pharmacother.2009 Jul;43(7):1347-53. Available from: DOI:10.1345/aph.1M064
Green K. Marijuana smoking vs cannabinoids for glaucoma therapy. Arch Ophthalmol.1998 Nov;116(11):1433–7. DOI:10.1001/archopht.116.11.1433
Gaston TE, Szaflarski M, Hansen B, et al. Quality of life in adults enrolled in an open-label study of cannabidiol (CBD) for treatment-resistant epilepsy. Epilepsy Behav. 2019 Jun;95:10-7. Available from: https://doi.org/10.1016/j.yebeh.2019.03.035.
Rosenthal F. The herb: hashish versus medieval Muslim society. Leiden, The Netherlands: Brill. c.1971