Canadian Cannabis, Avoiding the Potholes

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Presenting Author(s): Dr. Sam Chang, M.D., FRCP

Co-Author(s): Dr. Blair Richie, M.D., FRCP

Date and time: 22 Mar 2019 from 14:10 to 15:10

Location: Wildrose Salon C  Floor Map


  1. Be aware of the larger social, political, and financial aspects of Canadian Cannabis Policy;
  2. Be aware of the risks and benefits of Canadian Cannabis Policy esp the clinical and societal risks with particular focus on the neurodevelopmental risks in adolescence;
  3. Have a good understanding of specific, concrete recommendations physicians can take in dealing with this population of cannabis users clinically; and
  4. Special population needs for those at high risk esp in regards to those with ADHD.

Literature References

  1. Babson et al.  Cannabis, Cannabinoids, and Sleep: a Review of the Literature.  Curr Psychiatry Rep (2017) 19: 23
  2. Canadian Public Health Association: A Public Health Approach to the Legalization, Regulation and Restriction of Access to Cannabis. August 2016.
  3. CASA – National Center on Addiction and Substance Abuse at Columbia University. Missed opportunity: national survey of primary care physicians and patients on substance abuse. New York, NY: 2000.
  4. Castle et al.  Marijuana and Madness. 2nd ed.  Cambridge Medicine.  2012.
  5. Castle. Cannabis and psychosis: what causes what? F1000 Med Rep. 2013; 5: 1.
  6. CFPC, Authorizing Dried Cannabis for Chronic Pain and Anxiety. Sept 2014.
  7. CMA Submission: Legalization, Regulation and Restriction of Access to Marijuana: Government of Canada Task Force on Marijuana Legalization and Regulation: Aug 2016.
  8. CRAFFT. Center for Adolescent Substance Abuse Research, CeASAR, Children’s Hospital Boston. 2009.
  9. Devinsky et al. Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trial. Lancet Neurol 2016; 15: 270–78.
  10. Di Forti et al. Confirmation that the AKT1 (rs2494732) genotype influences the risk of psychosis in cannabis users. Biol Psychiatry. 2012 Nov 15;72(10):811-6. doi: 10.1016/j.biopsych.2012.06.020. Epub 2012 Jul 24.
  11. Feingold D et al. Cannabis use and the course and outcome of major depressive disorder: A population based longitudinal study. Psychiatry Res. 2017 May;251:225-234. doi: 10.1016/j.psychres.2017.02.027. Epub 2017 Feb 12.
  12. Fischer et al. Lower Risk Cannabis Use Guidelines for Canada (LRCUG): A Narrative Review of Evidence and Recommendations. Can J Public Health 2011;102(5):324-27.
  13. Health Canada 2012 Canadian Alcohol and Drug Use Monitoring Survey (CADUMS).
  14. Information for Health Care Professionals:Cannabis (marihuana, marijuana) and the cannabinoids. Health Canada. 2013.
  15. Jackson et al. Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies. Proc Natl Acad Sci USA 2016; 113(5):E500–E508
  16. Jacobus et al.  Changes in marijuana use symptoms and emotional functioning over 28-days of monitored abstinence in adolescent marijuana users. Psychopharmacology. December 2017, Volume 234, Issue 23–24, pp 3431–3442
  17. Johnston  et al. Monitoring the future national results on drug use 1975-2013: 2013 Overview: Key findings on adolescent drug use.
  18. Knight et al. Prevalence of positive substance abuse screen results among adolescent primary care patients. Arch Pediatr Adolesc Med. 2007 Nov;161(11):1035-41.
  19. Knight et al. Validity of the CRAFFT Substance Abuse Screening Test Among Adolescent Clinic Patients Arch Pediatr Adolesc Med. 2002;156(6):607-614.
  20. Marconi A et al. Meta-analysis of the Association Between the Level of Cannabis Use and Risk of Psychosis.  Schizophr Bull. 2016 Sep;42(5):1262-9. doi: 10.1093/schbul/sbw003. Epub 2016 Feb 15.
  21. Marijuana derivative 'shatter' poses risks, policy challenges; CBC news, Jan 2016;
  22. Meier et al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci USA 2012; 109(40):E2657-2564.
  23. Vogel. Public Health Experts Urge Realistic Pot Laws. CMAJ.  Sept 2016.
  24. Volkow et al.  Adverse Health Effects of Marijuana Use.  N Eng J Med 2014; 370:2219-27.
  25. Wang. One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function. J Am Heart Assoc. July 2016; 5: e003858.
  26. Yesavage et al.  Carry-over effects of marijuana intoxication on aircraft pilot performance: a preliminary report. Am J Psychiatry. 1985 Nov;142(11):1325-9.


There have been lots of confusion as to Canadian Cannabis Policy and its implications for Canadian Physicians. Trying to understand this as solely an outcome of scientific inquiry is inadequate given the very large sociocultural, political, and financial dimensions in Canadian Cannabis Use legislation. This presentation is an attempt to understand the bigger “systemic” picture of risks and benefits not only in the narrow clinical sense but also the larger societal context. An attempt is also made to distinguish between the different types of cannabinoids and their possible therapeutic and toxic qualities. Finally a key focus will be the practical applications of the knowledge gained, in the treatment of ADHD and the various comorbidities often present when substance abuse is concurrently active, including contrasting between the outcomes of optimal treatment versus inadequate treatment.


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