Cannabis-Induced Psychosis: A Review: Page 5 of 5
Cannabis-Induced Psychosis: A Review: Page 5 of 5
Carbamazepine has also been shown to have rapid effects when used as an adjunct to antipsychotics.11 Use of anti-seizure medication in CIP treatment has been hypothesized to reduce neuroleptic adverse effects, resulting in better tolerance of antipsychotics.10,11 These results suggest the use of adjunctive antiepileptics should be considered in CIP treatment strategies, although further studies in a broad range of patients with CIP are needed.
Abstaining from cannabis is the most beneficial and effective measure for preventing future CIP events; however, it is likely to be the most difficult to implement. Psychosocial intervention has a significant impact on early-phase psychosis, and when the intervention is initiated plays a role in disease outcomes. A delay in providing intensive psychosocial treatment has been associated with more negative symptoms compared with a delay in administrating antipsychotic medication.12 Employing cannabis- focused interventions with dependent patients who present with first-episode psychosis can decrease use in a clinically meaningful way and subjectively improve patient quality of life.
Compared with the standard of care, motivational interviewing significantly increases number of days abstinent from cannabis and aids in decreasing short-term consumption.13 Patients who are treated with motivational interviewing in addition to standard of care (combination of antipsychotic medication, regular office-based psychiatric contact, psychoeducation) are reported to also have more confidence and willingness to reduce cannabis use.
Patients with CIP who are unwilling or unable to decrease cannabis consumption may be protected from psychotic relapse with aripiprazole (10 mg/d). Its use suppresses the reemergence of psychosis without altering cannabis levels. However, no direct comparison has been made with aripiprazole and other antipsychotics in treating CIP. Clearly, well-controlled large studies of putative treatments for CIP are needed.
As more countries and states approve legalization, and marijuana becomes more accessible, CIP and other cannabis-related disorders are expected to increase. Efforts should be made by physicians to educate patients and discourage cannabis use. Just as there was an era of ignorance concerning the damaging effects of tobacco, today’s conceptions about cannabis may in fact be judged similarly in the future. The onus is on psychiatrists to take an evidence-based approach to this increasing problem.
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.