Assessment of CIP
DSM-5 categorizes cannabis-induced psychotic disorder as a substance-induced psychotic disorder. However, there are distinguishing characteristics of CIP that differentiate it from other psychotic disorders such as schizophrenia. Clear features of CIP are sudden onset of mood lability and paranoid symptoms, within 1 week of use but as early as 24 hours after use. CIP is commonly precipitated by a sudden increase in potency (eg, percent of THC content or quantity of cannabis consumption; typically, heavy users of cannabis consume more than 2 g/d). Criteria for CIP must exclude primary psychosis, and symptoms should be in excess of expected intoxication and withdrawal effects. A comparison of the clinical features of idiopathic psychosis versus CIP is provided in the Table.
When assessing for CIP, careful history taking is critical. Time of last drug ingestion will indicate if a patient’s psychotic symptoms are closely related to cannabis intoxication/withdrawal effects. While acute cannabis intoxication presents with a range of transient positive symptoms (paranoia, grandiosity, perceptual alterations), mood symptoms (anxiety), and cognitive deficits (working memory, verbal recall, attention), symptoms that persist beyond the effects of intoxication and withdrawal are better categorized as CIP, regardless of the route of administration (smoke inhalation, oral, intravenous). CIP has historically been associated with fewer negative symptoms than schizophrenia; however, without a clear timeline of use, distinguishing schizophrenia from CIP may prove difficult.
A diagnosis of primary psychosis (eg, schizophrenia) is warranted in the absence of heavy cannabis use or withdrawal (for at least 4 weeks), or if symptoms preceded onset of heavy use. The age at which psychotic symptoms emerge has not proved to be a helpful indicator; different studies show a conflicting median age of onset.
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.