The facts on marijuana might surprise you. Check out the top ten myths about marijuana usage and legalization:

MYTH #1: Smoking marijuana does not cause cancer

FACT: Smoking marijuana significantly increases your risk of lung cancer.

  • In a 40-year retrospective cohort study of 50,000 Swedish male conscripts, regular cannabis smoking was associated with a 2-fold risk of lung cancer, even after controlling for tobacco use and other factors. [1]

MYTH #2: Smoking marijuana does not give you lung disease

FACT: Marijuana smokers develop respiratory problems 20 years earlier than cigarette smokers.

  • Marijuana smokers are at an increased risk of respiratory problems including chronic bronchitis, as marijuana smoke is associated with inflammation of the large airways, increased airway resistance, and lung hyperinflation. Marijuana smokers also report increased rates of respiratory infections and pneumonia compared to nonsmokers. [2]
  • Researchers found that the mean age of marijuana-smoking patients with lung problems was 41, as opposed to the average age of 65 years for tobacco-smoking patients.[3]

MYTH #3: Smoking marijuana is safer than smoking tobacco

FACT: Marijuana smoke contains a higher concentration of dangerous chemicals than tobacco.

  • Ammonia levels are 20 times higher in the marijuana smoke than in the tobacco smoke, while hydrogen cyanide, nitric oxide and certain aromatic amines occurred at levels 3-5 times higher in the marijuana smoke. [4]
  • Studies of marijuana smokers have demonstrated consistent evidence of airway mucosal injury and inflammation as well as increased respiratory symptoms such as cough, phlegm production, and wheeze, similar to that seen in tobacco smokers. [5]

MYTH #4: Marijuana consumption does not affect your mental health

FACT: Persistent marijuana use before adulthood can cause permanent mental health impairment.

  • marijuana-bannerPersistent marijuana use before adulthood may permanently impair cognitive functioning and confer a higher risk of developing psychiatric diseases, such as schizophrenia and permanent working memory impairment. [6]
  • Adolescents are especially sensitive to repeated marijuana use, presumably because marijuana interferes with ongoing anatomical and physiological maturation of the brain, particularly the cerebral cortex. [7]

MYTH #5: Any mental health impacts from marijuana are temporary

FACT: Adolescent exposure to marijuana causes long-term mental health impairment.

  • marijuana-795-597Impairments in working memory, processing speed, perceptual reasoning, and other executive functions have been documented in long-term adolescent cannabis users. [8]
  • Adolescent exposure to marijuana induces long-term mental health impacts including deficits in exploratory behavior, long-term increases in anxiety measures and long-term deficits in sensorimotor gating. [9]
  • Marijuana use can produce long-lasting detrimental changes in brain function in adolescents.[10]

MYTH #6: Marijuana is not addictive

FACT: One in six people who use marijuana during adolescence will develop a cannabis use disorder.

  • weed-837125_1280Cannabis can be addictive. It is estimated that one in six individuals who use cannabis during adolescence will develop a cannabis use disorder, defined as a problematic pattern of cannabis use leading to clinically significant impairment or distress. Compared to alcohol and tobacco, cannabis use can develop more quickly into a substance use disorder among adolescents.[11]

MYTH #7: Legalizing marijuana will reduce organized crime

FACT: Organized crime has a very low involvement in the marijuana industry in Canada.

  • smoking-weed-and-guns-pistols-ammunition-colt-hd-i-617184Many of the reports the government has been relying on regarding organized crime in the cannabis market, while imparting valuable perspectives, often ignore peer reviewed Canadian and international research and contain unsubstantiated claims. [12]
  • The evidence base suggests that despite the illicit nature of the current cannabis market, it is not dominated by organized crime but rather by otherwise law-abiding citizens. [13]

MYTH #8: Legalizing marijuana will make it less attractive to youth

FACT: Marijuana use by youth has increased in US states after legalization.

  • Marijuana use by adolescents has grown steadily as more states enact various decriminalization laws. According to CDC data, more teens now smoke marijuana than cigarettes. [14]
  • After a period of decline in the last decade, marijuana use has generally increased among young people since 2007, corresponding with both its increased availability through limited legalization and a diminishing perception of the drug’s risks. [15]
  • In the two year average (2013/2014) since Colorado legalized recreational marijuana, youth past month marijuana use increased 20 percent compared to the two year average prior to legalization (2011/2012). [16]

MYTH #9: Marijuana consumption does not impair your driving ability

FACT: Marijuana use doubles the risk of a car crash.

  • UY9DnorCurrently, marijuana is the most common drug involved in drugged driving – a significant cause of highway crashes, injury, and death. New research shows that marijuana use doubles the risk of a car crash; habitual marijuana use is associated with increased risk of crash injury. [17]
  • Seminal reviews concluded that, based on relevant cognitive, memory/reaction and psychomotor ability impairments, drivers under the influence of cannabis have a two to three times elevated risk of being involved in (fatal or non-fatal) motor vehicle accidents. [18]

MYTH #10: Legalizing marijuana will not impact children

FACT: Incidents of marijuana poisoning of children tripled after legalization in the USA.

  • The legalization of marijuana has led to increased unintended exposure to marijuana among young children. By 2011, rates of poison center calls for accidental pediatric marijuana ingestion more than tripled in states that decriminalized marijuana before 2005. [19]
  • In states which passed legislation between 2005 and 2011 call rates increased nearly 11.5% per year. There was no similar increase in states that had not decriminalized marijuana as of December 31, 2011. [20]
  • Additionally, exposures in decriminalized states where marijuana use was legalized were more likely than those in non-legal states to present with moderate to severe symptoms requiring admission to a pediatric intensive care unit. The median age of children involved was 18-24 months. [21]

[1] Kalant H. Marihuana: Medicine, addictive substance, or both? A common-sense approach to the place of cannabis in medicine. Canadian Journal of Addiction Medicine 2013;4(3):p14.

[2] Barry, Rachel A MA; & Glantz, Stanton A PhD. (2016). A Public Health Analysis of Two Proposed Marijuana Legalization Initiatives for the 2016 California Ballot: Creating the New Tobacco Industry. UC San Francisco: Center for Tobacco Control Research and Education. Page 9.

[3] Blackwell Publishing. “Marijuana Smokers Face Rapid Lung Destruction — As Much As 20 Years Ahead Of Tobacco Smokers.” ScienceDaily. ScienceDaily, 27 January 2008. <www.sciencedaily.com/releases/2008/01/080123104017.htm>.

[4] American Chemical Society. “Marijuana Smoke Contains Higher Levels Of Certain Toxins Than Tobacco Smoke.” ScienceDaily. ScienceDaily, 18 December 2007. www.sciencedaily.com/releases/2007/12/071217110328.htm.

[5] Pletcher, Mark J. et al. “Association Between Marijuana Exposure and Pulmonary Function over 20 Years: The Coronary Artery Risk Development in Young Adults (CARDIA) Study.” JAMA : the journal of the American Medical Association 307.2 (2012): 10.1001/jama.2011.1961. PMC. Web. 16 Aug. 2016. Page 173.

[6] Sylvina M Raver, Sarah P Haughwout and Asaf Keller, ‘Adolescent Cannabinoid Exposure Permanently Suppresses Cortical Oscillations in Adult Mice’, Neuropsychopharmacology July 4th 2013, doi:10.1038/npp.2013.

[7] Ibid.

[8] Sylvina M Raver, Sarah P Haughwout and Asaf Keller, ‘Adolescent Cannabinoid Exposure Permanently Suppresses Cortical Oscillations in Adult Mice’, Neuropsychopharmacology July 4th 2013, doi:10.1038/npp.2013.164

[9] Justine Renard, Laura G. Rosen, Michael Loureiro, Cleusa De Oliveira, Susanne Schmid, Walter J. Rushlow, and Steven R. Laviolette. Adolescent Cannabinoid Exposure Induces a Persistent Sub-Cortical Hyper-Dopaminergic State and Associated Molecular Adaptations in the Prefrontal Cortex Cereb. Cerebral Cortex first published online January 4, 2016 doi:10.1093/cercor/bhv335

[10] Barry, Rachel A MA; & Glantz, Stanton A PhD. (2016). A Public Health Analysis of Two Proposed Marijuana Legalization Initiatives for the 2016 California Ballot: Creating the New Tobacco Industry. UC San Francisco: Center for Tobacco Control Research and Education. Page 9.

[11] George, T., & Vaccarino, F. (Eds.). (2015). Substance abuse in Canada: The Effects of Cannabis Use during Adolescence (Report in Short). Ottawa, ON: Canadian Centre on Substance Abuse.

[12] Boyd, Neil et al. “Organized Crime in the Cannabis Market: Evidence and Implications.” Canadian Drug Policy Coalition Submission to the Cannabis Legalization Task Force. 2016.

[13] Ibid.

[14] Anderson, Jane, MD, FCP, and Donald Hagler, MD, FCP. “Marijuana Use: Detrimental to Youth.” American College of Pediatricians. N.p., 29 Apr. 2016. Web. 23 Aug. 2016.

[15] Ibid.

[16] “The Legalization of Marijuana inn Colorado: The Impact.” 2016. Rocky Mountain High Intensity Drug Trafficking Area. http://www.rmhidta.org/html/FINAL%20NSDUH%20Results-%20Jan%202016%20Release.pdf

[17] American Society of Addiction Medicine (ASAM). (2012). White Paper on State-Level Proposals to Legalize Marijuana. Retrieved from http://www.asam.org/advocacy/find-a-policy-statement/view-policy-statement/public-policy-statements/2014/07/24/white-paper-on-state-level-proposals-to-legalize-marijuana. Accessed 2016 Aug 24.

[18] Fischer B, Imtiaz S, Rudzinski K, Rehm J. Crude estimates of cannabis-attributable mortality and morbidity in Canada-implications for public health focused intervention priorities. J Public Health (Oxf). 2016; 38(1):183-188. doi:10.1093/pubmed/fdv005

[19] Anderson, Jane, MD, FCP, and Donald Hagler, MD, FCP. “Marijuana Use: Detrimental to Youth.” American College of Pediatricians. N.p., 29 Apr. 2016. Web. 23 Aug. 2016.

[20] Anderson, Jane, MD, FCP, and Donald Hagler, MD, FCP. “Marijuana Use: Detrimental to Youth.” American College of Pediatricians. N.p., 29 Apr. 2016. Web. 23 Aug. 2016.

[21] Anderson, Jane, MD, FCP, and Donald Hagler, MD, FCP. “Marijuana Use: Detrimental to Youth.” American College of Pediatricians. N.p., 29 Apr. 2016. Web. 23 Aug. 2016.