Welcome to PsychEd — the psychiatry podcast for medical learners, by medical learners. This episode covers the relationship between cannabis and psychotic disorders, as well as the potential impact of cannabis legalization in Canada, with our special guest Dr. Nitin Chopra. This episode was originated by Dr. Luke Fraccaro for his Grand Rounds.
The learning objectives for this episode are as follows:
By the end of this episode, you should be able to…
Briefly summarize the effects of cannabis on mental health and cognition, with a focus on psychosis.
Appreciate the evidence for cannabis use as a potential cause of persistent psychotic disorders.
Discuss the possible impact that recent cannabis legislation may have had on cannabis use and psychosis in Canada.
Guest expert Dr. Nitin Chopra is an addictions psychiatrist at the Centre for Addiction and Mental Health (CAMH) and is an Assistant Professor in the Department of Psychiatry at the University of Toronto. He has an interest in concurrent disorders and is a staff psychiatrist on the Concurrent Addictions Inpatient Treatment Service and Concurrent Outpatient Medical and Psychosocial Addiction Support Service. Through his work on the Psychiatry Addictions Capacity Building and Consultation Service (PACCS) at CAMH and the Addiction Medicine and Psychosocial Addictions ECHO program, he is evolving into a leader in capacity building and education for addictions treatment. Furthermore, Dr. Chopra also works on the Early Psychosis Unit at CAMH and has extensive clinical experience working with patients experiencing psychosis, often with comorbid cannabis and other substance use.
Grand Rounds Presenter: Dr. Luke Fraccaro (PGY3)
Produced by: Dr. Luke Fraccaro (PGY3), Dr. Alex Raben (staff psychiatrist), and Josh Benchaya (MS4)
Hosts: Dr. Luke Fraccaro (PGY3), Dr. Alex Raben (staff psychiatrist), and Josh Benchaya (MS4)
Audio editing by: Dr. Luke Fraccaro (PGY3)
Show notes by: Dr. Luke Fraccaro (PGY3)
Conflicts of Interest: There are no known conflict of interests to report
Topics:
0:00 - Introduction
2:50 - Objectives
3:55 - Case example
7:25 - Overview of cannabis effects on mental health
10:45 - Differentiating clinically between cannabis-induced psychosis and a primary psychotic disorder
13:11 - Cannabis causing acute psychotic symptoms
14:15 - Back to the case
16:05 - Overlapping risk factors for cannabis use and psychotic disorders
18:14 - Cannabis use as a potential cause of persistent psychotic disorders (reviewing the evidence)
30:14 - Summary of the relationship between cannabis and psychosis and how to apply it clinically
35:20 - Cannabis legalization in Canada
39:45 - Canadian studies on potential impact of cannabis legalization on psychosis
44:33 - Brief review of American studies on potential impact of cannabis legalization on psychosis
46:35 - Summary of potential impact of legalization
47:42 - Questions and discussion
1:06:15 - Summary and outro
Resources:
Canada’s Lower-Risk Cannabis Use Guideline: https://www.camh.ca/-/media/files/lrcug_professional-pdf.pdf
Cannabis legalization and regulation in Canada: https://www.canada.ca/en/health-canada/programs/engaging-cannabis-legalization-regulation-canada-taking-stock-progress/document.html
References:
American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision. Arlington, VA: American Psychiatric Association, 2022.
Tourjman SV, Buck G, Jutras-Aswad D, Khullar A, McInerney S, Saraf G, Pinto JV, Potvin S, Poulin MJ, Frey BN, Kennedy SH, Lam RW, MacQueen G, Milev R, Parikh SV, Ravindran A, McIntyre RS, Schaffer A, Taylor VH, van Ameringen M, Yatham LN, Beaulieu S. Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: A Systematic Review and Recommendations of Cannabis use in Bipolar Disorder and Major Depressive Disorder. Can J Psychiatry. 2022 Jun 16:7067437221099769. doi: 10.1177/07067437221099769. Epub ahead of print. PMID: 35711159.
Xue S, Husain MI, Zhao H, Ravindran AV. Cannabis Use and Prospective Long-Term Association with Anxiety: A Systematic Review and Meta-Analysis of Longitudinal Studies. Can J Psychiatry. 2021 Feb;66(2):126-138. doi: 10.1177/0706743720952251. Epub 2020 Sep 10. PMID: 32909828; PMCID: PMC7918873.
Broyd SJ, van Hell HH, Beale C, Yücel M, Solowij N. Acute and Chronic Effects of Cannabinoids on Human Cognition-A Systematic Review. Biol Psychiatry. 2016 Apr 1;79(7):557-67. doi: 10.1016/j.biopsych.2015.12.002. Epub 2015 Dec 8. PMID: 26858214.
Wilkinson ST, Radhakrishnan R, D'Souza DC. Impact of Cannabis Use on the Development of Psychotic Disorders. Curr Addict Rep. 2014 Jun 1;1(2):115-128. doi: 10.1007/s40429-014-0018-7. PMID: 25767748; PMCID: PMC4352721.
Hindley G, Beck K, Borgan F, Ginestet CE, McCutcheon R, Kleinloog D, Ganesh S, Radhakrishnan R, D'Souza DC, Howes OD. Psychiatric symptoms caused by cannabis constituents: a systematic review and meta-analysis. Lancet Psychiatry. 2020 Apr;7(4):344-353. doi: 10.1016/S2215-0366(20)30074-2. Epub 2020 Mar 17. PMID: 32197092; PMCID: PMC7738353.
Ksir, C., Hart, C.L. Cannabis and Psychosis: a Critical Overview of the Relationship. Curr Psychiatry Rep 18, 12 (2016).
Ganesh S, D'Souza DC. Cannabis and Psychosis: Recent Epidemiological Findings Continuing the "Causality Debate". Am J Psychiatry. 2022 Jan;179(1):8-10. doi: 10.1176/appi.ajp.2021.21111126. PMID: 34974754.
Hasan A, von Keller R, Friemel CM, Hall W, Schneider M, Koethe D, Leweke FM, Strube W, Hoch E. Cannabis use and psychosis: a review of reviews. Eur Arch Psychiatry Clin Neurosci. 2020 Jun;270(4):403-412. doi: 10.1007/s00406-019-01068-z. Epub 2019 Sep 28. PMID: 31563981.
Petrilli K, Ofori S, Hines L, Taylor G, Adams S, Freeman TP. Association of cannabis potency with mental ill health and addiction: a systematic review. Lancet Psychiatry. 2022 Sep;9(9):736-750. doi: 10.1016/S2215-0366(22)00161-4. Epub 2022 Jul 25. PMID: 35901795.
Buchy L, Perkins D, Woods SW, Liu L, Addington J. Impact of substance use on conversion to psychosis in youth at clinical high risk of psychosis. Schizophr Res. 2014 Jul;156(2-3):277-80. doi: 10.1016/j.schres.2014.04.021. Epub 2014 May 14. PMID: 24837058; PMCID: PMC4082820.
Gillespie NA, Kendler KS. Use of Genetically Informed Methods to Clarify the Nature of the Association Between Cannabis Use and Risk for Schizophrenia. JAMA Psychiatry. 2021 May 1;78(5):467-468. doi: 10.1001/jamapsychiatry.2020.3564. PMID: 33146687.
Johnson EC, Hatoum AS, Deak JD, Polimanti R, Murray RM, Edenberg HJ, Gelernter J, Di Forti M, Agrawal A. The relationship between cannabis and schizophrenia: a genetically informed perspective. Addiction. 2021 Nov;116(11):3227-3234. doi: 10.1111/add.15534. Epub 2021 May 19. PMID: 33950550; PMCID: PMC8492483.
Fischer, B., Lee, A., Robinson, T. et al. An overview of select cannabis use and supply indicators pre- and post-legalization in Canada. Subst Abuse Treat Prev Policy 16, 77 (2021). https://doi.org/10.1186/s13011-021-00405-7
Myran DT, Imtiaz S, Konikoff L, Douglas L, Elton-Marshall T. Changes in health harms due to cannabis following legalisation of non-medical cannabis in Canada in context of cannabis commercialisation: A scoping review. Drug Alcohol Rev. 2023 Feb;42(2):277-298. doi: 10.1111/dar.13546. Epub 2022 Sep 27. PMID: 36165188.
Vignault C, Massé A, Gouron D, Quintin J, Asli KD, Semaan W. The Potential Impact of Recreational Cannabis Legalization on the Prevalence of Cannabis Use Disorder and Psychotic Disorders: A Retrospective Observational Study. Can J Psychiatry. 2021 Dec;66(12):1069-1076. doi: 10.1177/0706743720984684. Epub 2021 Feb 11. PMID: 33567893; PMCID: PMC8689454.
Callaghan RC, Sanches M, Murray RM, Konefal S, Maloney-Hall B, Kish SJ. Associations Between Canada's Cannabis Legalization and Emergency Department Presentations for Transient Cannabis-Induced Psychosis and Schizophrenia Conditions: Ontario and Alberta, 2015-2019. Can J Psychiatry. 2022 Aug;67(8):616-625. doi: 10.1177/07067437211070650. Epub 2022 Jan 12. PMID: 35019734; PMCID: PMC9301152.
D'Souza DC, DiForti M, Ganesh S, George TP, Hall W, Hjorthøj C, Howes O, Keshavan M, Murray RM, Nguyen TB, Pearlson GD, Ranganathan M, Selloni A, Solowij N, Spinazzola E. Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis. World J Biol Psychiatry. 2022 Dec;23(10):719-742. doi: 10.1080/15622975.2022.2038797. Epub 2022 Mar 22. PMID: 35315315.
Wang, G. S., Buttorff, C., Wilks, A., Schwam, D., Tung, G., & Pacula, R. L. (2022). Impact of cannabis legalization on healthcare utilization for psychosis and schizophrenia in Colorado. International Journal of Drug Policy, 104, 103685.
Kim, H. S., & Monte, A. A. (2016). Colorado Cannabis Legalization and Its Effect on Emergency Care. Annals of emergency medicine, 68(1), 71–75. https://doi-org.proxy3.library.mcgill.ca/10.1016/j.annemergmed.2016.01.004
CPA Note: The views expressed in this podcast do not necessarily reflect those of the Canadian Psychiatric Association.
For more PsychEd, follow us on Twitter (@psychedpodcast), Facebook (PsychEd Podcast), and Instagram (@psyched.podcast). You can provide feedback by email at psychedpodcast@gmail.com. For more information, visit our website at psychedpodcast.org.