Cannabis is the most widely used illicit drug in the United States, and trends show increasing use in the general population. As cannabis consumption rises, there has been significant emerging evidence for cannabis-related risks to health.1
Numerous lines of evidence suggest a correlation between cannabis consumption and a variety of psychiatric conditions, including cannabis-induced psychosis (CIP). While it can be difficult to differentiate CIP from other psychoses, CIP holds distinguishing characteristics, which may aid in its diagnosis. Given the increasing push toward cannabis legalization, assessing CIP and employing timely treatments is critical.
Specifically in youth, there is a direct relationship between cannabis use and its risks. The lack of knowledge surrounding its detrimental effects, combined with misunderstandings related to its therapeutic effects, has potential for catastrophic results.
Ms. J, a 19-year-old college sophomore, was admitted to the Early Psychosis Unit at the Centre for Addiction and Mental Health (CAMH) displaying signs of agitation and acute psychosis. Her roommates had noted that her behavior had become increasingly bizarre, and she had isolated herself over the past month. She began smoking marijuana at the age of 17 and since starting college used it daily.
Ms. J exhibited signs of paranoia, believing other students in her dorm were stealing from her and trying to poison her. She remained adamant that all her problems were rooted in the competitive environment of the university and that smoking marijuana aided in keeping her sanity. In a sense, she was self-medicating. Her clinical presentation was consistent with a diagnosis of CIP.
After the hospitalization, she received outpatient case management services in the Early Psychosis Program at CAMH, which included motivational interviewing to raise her awareness about the importance of abstaining from cannabis use. She has been abstinent from cannabis for more than a year with no evidence of psychosis; she recently returned to school to finish her degree.
Epidemiology of CIP
Reports have shown a staggering increase in cannabis-related emergency department (ED) visits in recent years. In 2011, the Substance Abuse and Mental Health Services Administration (SAMHSA) and Drug Abuse Warning Network (DAWN) estimated a total of 1.25 million illicit-drug–related ED visits across the US, of which 455,668 were marijuana related.2 A similar report published in 2015 by the Washington Poison Center Toxic Trends Report showed a dramatic increase in cannabis-related ED visits.3 In states with recent legalization of recreational cannabis, similar trends were seen.4
States with medicinal marijuana have also shown a dramatic rise in cannabis-related ED visits. Moreover, states where marijuana is still illegal also showed increases.5 This widespread increase is postulated to be in part due to the easy accessibility of the drug, which contributes to over-intoxication and subsequent symptoms. Overall, from 2005 to 2011, there has been a dramatic rise in cannabis-related ED visits among all age groups and genders.
Dr. Grewal is a recent MD graduate of Avalon University School of Medicine in Willemstad, Curaçao. Dr. George is Chief of Addictions at the Centre for Addiction and Mental Health (CAMH) and Professor and Director of the Division of Brain and Therapeutics in the Department of Psychiatry at the University of Toronto. Dr. George’s research is supported by the Canadian Institutes of Health Research (CIHR), the CAMH Foundation, and the National Institute on Drug Abuse (NIDA).
Dr. Grewal reports no conflict of interest concerning the subject matter of this article. Dr. George reports that he is a consultant to Novartis, the American College of Neuropsychology, and the Canadian Center for Substance Use and Addiction.
1. Fischer B, Imtiaz Z, Rudzinski K, Rehm J. Crude estimates of cannabis-attributable mortality and morbidity in Canada–implications for public health focused intervention priorities. J Public Health. 2015;38:183-188.
2. Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality. The DAWN Report: Highlights of the 2011 Drug Abuse Warning Network (DAWN) Findings on Drug-Related Emergency Department Visits. Rockville, MD; February 22, 2013.
3. Washington Poison Center. Toxic Trends Report: 2015 Annual Cannabis Report. http://www.wapc.org/toxic-trends/marijuana-and-you/2015annualcannabisreport/. Accessed June 9, 2017.
4. Kim HS, Monte AA. Colorado cannabis legalization and its effect on emergency care. Ann Emerg Med. 2016;68:71-75.
5. Brauser D. Cannabis-related ED visits rise in states with legalized use. Medscape. December 16, 2014. http://www.medscape.com/viewarticle/836663. Accessed June 9, 2017.
6. Bloomfield MA, Morgan CJ, Egerton A, et al. Dopaminergic function in cannabis users and its relationship to cannabis-induced psychotic symptoms. Biol Psychiatry. 2014;75:470-478.
7. Henquet C, Rosa A, Delespaul P, et al. COMT Val158Met moderation of cannabis-induced psychosis: a momentary assessment study of ‘switching on’ hallucinations in the flow of daily life. Acta Psychiatr Scand. 2009;119:156-160.
8. Arendt M, Rosenberg R, Foldager L, et al. Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases. Br J Psychiatry. 2005;187:510-515.
9. Rottanburg D, Robins AH, Ben-Arie O, et al. Cannabis-associated psychosis with hypomanic features. Lancet. 1983;320:1364-1366.
10. Perera T, Webler R. Cannabis-induced psychosis and an antipsychotic-induced seizure: a case report. Prim Care Companion CNS Disord. 2017;19(1). doi: 10.4088/PCC.16l01993.
11. Leweke F, Emrich M, Hinderk M. Carbamazepine as an adjunct in the treatment of schizophrenia-like psychosis related to cannabis abuse. Int Clin Psychopharmacol. 1999;14:37-39.
12. de Haan L, Linszen DH, Lenior ME, et al. Duration of untreated psychosis and outcome of schizophrenia: delay in intensive psychosocial treatment versus delay in treatment with antipsychotic medication. Schizophr Bull. 2003;29:341-348.
13. Bonsack C, Gibellini Manetti S, Favrod J, et al. Motivational intervention to reduce cannabis use in young people with psychosis: a randomized controlled trial. Psychother Psychosom. 2011;80:287-297.