Interest in the relationship between cannabis use and psychosis has increased dramatically in recent years, in part because of concerns related to the growing availability of cannabis and potential risks to health and human functioning. There now exists a plethora of scientific articles addressing this issue, but few provide a clear verdict about the causal nature of the cannabis-psychosis association. Here, we review recent research reports on cannabis and psychosis, giving particular attention to how each report provides evidence relating to two hypotheses: (1) cannabis as a contributing cause and (2) shared vulnerability. Two primary kinds of data are brought to bear on this issue: studies done with schizophrenic patients and studies of first-episode psychosis. Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis. The role of early and heavy cannabis use as a prodromal sign merits further examination, along with a variety of other problem behaviors (e.g., early or heavy use of cigarettes or alcohol and poor school performance). Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
Papers of particular interest, published recently, have been highlighted as: • Of impotance, •• Of major importance
Bagot KS, Milin R, Kaminer Y. Adolescent initiation of cannabis use and early-onset psychosis. Subst Abuse Off Publ Assoc Med Educ Res Subst Abuse. 2015 Mar 16;0.
Gage SH, Zammit S, Hickman M. Stronger evidence is needed before accepting that cannabis plays an important role in the aetiology of schizophrenia in the population. F1000 Med Rep [Internet]. 2013;5. Available from: http://www.f1000.com/prime/reports/m/5/2/
Allegri F, Belvederi Murri M, Paparelli A, Marcacci T, Braca M, Menchetti M, et al. Current cannabis use and age of psychosis onset: a gender-mediated relationship? Results from an 8-year FEP incidence study in Bologna. Psychiatry Res. 2013;210(1):368–70.
Bahorik AL, Newhill CE, Eack SM. Neurocognitive functioning of individuals with schizophrenia: using and not using drugs. Schizophr Bull. 2014;40(4):856–67.
Manrique-Garcia E, Zammit S, Dalman C, Hemmingsson T, Andreasson S, Allebeck P. Cannabis, schizophrenia and other non-affective psychoses: 35 years of follow-up of a population-based cohort. Psychol Med. 2012;42(06):1321–8.
Lejoyeux M, Basquin A, Koch M, Embouazza H, Chalvin F, Ilongo M. Cannabis use and dependence among French schizophrenic inpatients. Front Psychiatry [Internet]. 2014;5. Available from: http://journal.frontiersin.org/article/10.3389/fpsyt.2014.00082/abstract
Paruk S, Burns JK, Caplan R. Cannabis use and family history in adolescent first episode psychosis in Durban, South Africa. J Child Adolesc Ment Health. 2013;25(1):61–8.
Jessor R. Predicting time of onset of marijuana use: a developmental study of high school youth. J Consult Clin Psychol. 1976;44(1):125–34.
Stone AL, Becker LG, Huber AM, Catalano RF. Review of risk and protective factors of substance use and problem use in emerging adulthood. Addict Behav. 2012;37(7):747–75.
Jessor R, Turbin MS. Parsing protection and risk for problem behavior versus pro-social behavior among US and Chinese adolescents. J Youth Adolesc. 2014;43(7):1037–51.
American Psychiatric Association, American Psychiatric Association, editors. Diagnostic and statistical manual of mental disorders: DSM-5. 5th ed. Washington, D.C: American Psychiatric Association; 2013. 947 p
Fuller Torrey E, Simmons W, Yolken RH. Is childhood cat ownership a risk factor for schizophrenia later in life? Schizophr Res. 2015;165(1):1–2.
Broussard B, Kelley ME, Wan CR, Cristofaro SL, Crisafio A, Haggard PJ, et al. Demographic, socio-environmental, and substance-related predictors of duration of untreated psychosis (DUP). Schizophr Res. 2013;148(1–3):93–8. This study found that combining information from childhood maltreatment, school adjustment, and social adjustment predicted duration of untreated psychosis as well as did adolescent cannabis use.
Hill AB. The environment and disease: association or causation? Proc R Soc Med. 1965;58(5):295–300.
Haller S, Curtis L, Badan M, Bessero S, Albom M, Chantraine F, et al. Combined grey matter VBM and white matter TBSS analysis in young first episode psychosis patients with and without cannabis consumption. Brain Topogr. 2013;26(4):641–7.
McLaren JA, Silins E, Hutchinson D, Mattick RP, Hall W. Assessing evidence for a causal link between cannabis and psychosis: a review of cohort studies. Int J Drug Policy. 2010;21(1):10–9.
van Nierop M, Janssens M, Genetic Risk OUtcome of Psychosis (GROUP) Investigators, Bruggeman R, Cahn W, de Haan L, et al. Evidence that transition from health to psychotic disorder can be traced to semi-ubiquitous environmental effects operating against background genetic risk. Clelland JD, editor. PLoS ONE. 2013;8(11):e76690.
Di Forti M, Marconi A, Carra E, Fraietta S, Trotta A, Bonomo M, et al. Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study. Lancet Psychiatry. 2015;2(3):233–8.
Di Forti M, Sallis H, Allegri F, Trotta A, Ferraro L, Stilo SA, et al. Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users. Schizophr Bull. 2014;40(6):1509–17.
Donoghue K, Doody GA, Murray RM, Jones PB, Morgan C, Dazzan P, et al. Cannabis use, gender and age of onset of schizophrenia: data from the AESOP study. Psychiatry Res. 2014;215(3):528–32.
Stefanis NC, Dragovic M, Power BD, Jablensky A, Castle D, Morgan VA. The effect of drug use on the age at onset of psychotic disorders in an Australian cohort. Schizophr Res. 2014;156(2–3):211–6.
Stone JM, Fisher HL, Major B, Chisholm B, Woolley J, Lawrence J, et al. Cannabis use and first-episode psychosis: relationship with manic and psychotic symptoms, and with age at presentation. Psychol Med. 2014;44(03):499–506.
Tosato S, Lasalvia A, Bonetto C, Mazzoncini R, Cristofalo D, De Santi K, et al. The impact of cannabis use on age of onset and clinical characteristics in first-episode psychotic patients. Data from the Psychosis Incident Cohort Outcome Study (PICOS). J Psychiatr Res. 2013;47(4):438–44.
Degenhardt L, Ferrari AJ, Calabria B, Hall WD, Norman RE, McGrath J, et al. The global epidemiology and contribution of cannabis use and dependence to the global burden of disease: results from the GBD 2010 study. Brody JP, editor. PLoS ONE. 2013 Oct 24;8(10):e76635. This models the global burden of disease related to the influence of cannabis dependence and schizophrenia and points out that the overall health impact of this issue is very small.
Dharmawardene V, Menkes DB. Substance use disorders in New Zealand adults with severe mental illness: descriptive study of an acute inpatient population. Aust Psychiatry. 2015;23(3):236–40.
Gurillo P, Jauhar S, Murray RM, MacCabe JH. Does tobacco use cause psychosis? Systematic review and meta-analysis. Lancet Psychiatry [Internet]. 2015; Available from: http://linkinghub.elsevier.com/retrieve/pii/S2215036615001522
Kendler KS, Lönn SL, Sundquist J, Sundquist K. Smoking and Schizophrenia in Population Cohorts of Swedish Women and Men: A Prospective Co-Relative Control Study. Am J Psychiatry. 2015 5;appiajp201515010126. This study does not address cannabis use, but its methods and findings for tobacco should be considered carefully by anyone attempting to study cannabis and schizophrenia.
McGrath JJ, Alati R, Clavarino A, Williams GM, Bor W, Najman JM, et al. Age at first tobacco use and risk of subsequent psychosis-related outcomes: a birth cohort study. Aust N Z J Psychiatry [Internet]. 2015; Available from: http://anp.sagepub.com/lookup/doi/10.1177/0004867415587341
Rabin RA, Giddens JL, George TP. Relationship between tobacco and cannabis use status in outpatients with schizophrenia. Am J Addict. 2014;23(2):170–5.
Fernández-Calderón D, Fernández F, Ruiz-Curado S, Verdejo-García A, Lozano ÓM. Profiles of substance use disorders in patients of therapeutic communities: link to social, medical and psychiatric characteristics. Drug Alcohol Depend. 2015;149:31–9.
Sara GE, Burgess PM, Malhi GS, Whiteford HA, Hall WC. Stimulant and other substance use disorders in schizophrenia: prevalence, correlates and impacts in a population sample. Aust N Z J Psychiatry. 2014;48(11):1036–47. This large Australian study found greater risk ratios for schizophrenia associated with stimulant use or combined stimulant/cannabis use than for cannabis use alone.
Auther AM, Cadenhead KS, Carrión RE, Addington J, Bearden CE, Cannon TD, et al. Alcohol confounds relationship between cannabis misuse and psychosis conversion in a high-risk sample. Acta Psychiatr Scand. 2015;132(1):60–8.
Hartz SM, Pato CN, Medeiros H, Cavazos-Rehg P, Sobell JL, Knowles JA, et al. Comorbidity of severe psychotic disorders with measures of substance use. JAMA Psychiatry. 2014;71(3):248. I This very large study of severe psychosis found higher odds ratios for tobacco use, heavy alcohol use, and recreational drug use than for cannabis use.
Nesvåg R, Knudsen GP, Bakken IJ, Høye A, Ystrom E, Surén P, et al. Substance use disorders in schizophrenia, bipolar disorder, and depressive illness: a registry-based study. Soc Psychiatry Psychiatr Epidemiol. 2015; This study took the unusual step of including a variety od psychiatric disorders and a variety of substance use in the same study. There was a clear association between cannabis use and schizophrenia, but this study makes it clear that this is not a unique relationship.
Arias F, Szerman N, Vega P, Mesias B, Basurte I, Morant C, et al. Abuse or dependence on cannabis and other psychiatric disorders. Madrid study on dual pathology prevalence. Actas Esp Psiquiatr. 2013;41(2):122–9.
Chadwick B, Miller ML, Hurd YL. Cannabis use during adolescent development: susceptibility to psychiatric illness. Front Psychiatry [Internet]. 2013;4. Available from: http://journal.frontiersin.org/article/10.3389/fpsyt.2013.00129/abstract
Lagerberg TV, Kvitland LR, Aminoff SR, Aas M, Ringen PA, Andreassen OA, et al. Indications of a dose–response relationship between cannabis use and age at onset in bipolar disorder. Psychiatry Res. 2014;2015(1):101–4.
Guillem E, Arbabzadeh-Bouchez S, Vorspan F, Bellivier F. Comorbidity in 207 cannabis users in a specific outpatient setting. L’Encéphale. 2015;41 Suppl 1:S7–S12.
Giordano GN, Ohlsson H, Sundquist K, Sundquist J, Kendler KS. The association between cannabis abuse and subsequent schizophrenia: a Swedish national co-relative control study. Psychol Med. 2014;3:1–8. This large registry study found that the majority of the association between cannabis and schizophrenia could be attributed to familial factors.
Davis GP, Compton MT, Wang S, Levin FR, Blanco C. Association between cannabis use, psychosis, and schizotypal personality disorder: findings from the National Epidemiologic Survey on Alcohol and Related Conditions. Schizophr Res. 2013;151(1–3):197–202.
Bossong MG, Mehta MA, van Berckel BNM, Howes OD, Kahn RS, Stokes PRA. Further human evidence for striatal dopamine release induced by administration of ∆9-tetrahydrocannabinol (THC): selectivity to limbic striatum. Psychopharmacology (Berl). 2015;232(15):2723–9.
Bioque M, García-Bueno B, Macdowell KS, Meseguer A, Saiz PA, Parellada M, et al. Peripheral endocannabinoid system dysregulation in first-episode psychosis. Neuropsychopharmacol Off Publ Am Coll Neuropsychopharmacol. 2013;38(13):2568–77.
Suárez-Pinilla P, Roiz-Santiañez R, Ortiz-García de la Foz V, Guest PC, Ayesa-Arriola R, Córdova-Palomera A, et al. Brain structural and clinical changes after first episode psychosis: Focus on cannabinoid receptor 1 polymorphisms. Psychiatry Res Neuroimaging [Internet]. 2015; Available from: http://linkinghub.elsevier.com/retrieve/pii/S0925492715001122
Volk DW, Eggan SM, Horti AG, Wong DF, Lewis DA. Reciprocal alterations in cortical cannabinoid receptor 1 binding relative to protein immunoreactivity and transcript levels in schizophrenia. Schizophr Res. 2014;159(1):124–9.
Koenders L, Machielsen MWJ, van der Meer FJ, van Gasselt ACM, Meijer CJ, van den Brink W, et al. Brain volume in male patients with recent onset schizophrenia with and without cannabis use disorders. J Psychiatry Neurosci JPN. 2015;40(3):197–206.
Malchow B, Hasan A, Schneider-Axmann T, Jatzko A, Gruber O, Schmitt A, et al. Effects of cannabis and familial loading on subcortical brain volumes in first-episode schizophrenia. Eur Arch Psychiatry Clin Neurosci. 2013;263(S2):155–68.
Onwuameze OE, Nam KW, Epping EA, Wassink TH, Ziebell S, Andreasen NC, et al. MAPK14 and CNR1 gene variant interactions: effects on brain volume deficits in schizophrenia patients with marijuana misuse. Psychol Med. 2013;43(03):619–31.
Epstein KA, Kumra S. Altered cortical maturation in adolescent cannabis users with and without schizophrenia. Schizophr Res. 2015;162(1–3):143–52.
Solowij N, Walterfang M, Lubman DI, Whittle S, Lorenzetti V, Styner M, et al. Alteration to hippocampal shape in cannabis users with and without schizophrenia. Schizophr Res. 2013;143(1):179–84.
Fischer AS, Whitfield-Gabrieli S, Roth RM, Brunette MF, Green AI. Impaired functional connectivity of brain reward circuitry in patients with schizophrenia and cannabis use disorder: effects of cannabis and THC. Schizophr Res. 2014;158(1–3):176–82.
Greenwood L, Broyd SJ, Croft R, Todd J, Michie PT, Johnstone S, et al. Chronic effects of cannabis use on the auditory mismatch negativity. Biol Psychiatry. 2014;75(6):449–58.
Herzig DA, Sullivan S, Lewis G, Corcoran R, Drake R, Evans J, et al. Hemispheric language asymmetry in first episode psychosis and schizotypy: the role of cannabis consumption and cognitive disorganization. Schizophr Bull. 2015;41 Suppl 2:S455–64.
Monteleone P, Di Filippo C, Fabrazzo M, Milano W, Martiadis V, Corrivetti G, et al. Flattened cortisol awakening response in chronic patients with schizophrenia onset after cannabis exposure. Psychiatry Res. 2014;215(2):263–7.
Muller-Vahl K, Emrich H. Cannabis and schizophrenia: towards a cannabinoid hypothesis of schizophrenia. Exp Rev Neurother. 2008;8(7):1037–48.
Morena M, Patel S, Bains J, Hill, M. Neurobiological interactions between stress and the endocannabinoid system. Neuropsychopharmacol Rev. 2015
Martin AK, Robinson G, Reutens D, Mowry B. Cannabis abuse and age at onset in schizophrenia patients with large, rare copy number variants. Schizophr Res. 2014;155(1–3):21–5; Available from: http://www.nature.com/npp/journal/vaop/ncurrent/full/npp2015166a.html
Veling W, Mackenbach JP, van Os J, Hoek HW. Cannabis use and genetic predisposition for schizophrenia: a case-control study. Psychol Med [Internet]. 2008;38(09). Available from: http://www.journals.cambridge.org/abstract_S0033291708003474
Aberg KA, Liu Y, Bukszár J, McClay JL, Khachane AN, Andreassen OA, et al. A comprehensive family-based replication study of schizophrenia genes. JAMA Psychiatry. 2013;70(6):573.
Power RA, Verweij KJH, Zuhair M, Montgomery GW, Henders AK, Heath AC, et al. Genetic predisposition to schizophrenia associated with increased use of cannabis. Mol Psychiatry. 2014;19(11):1201–4.
Proal AC, Fleming J, Galvez-Buccollini JA, DeLisi LE. A controlled family study of cannabis users with and without psychosis. Schizophr Res. 2014;152(1):283–8. This well-designed study used a 2 × 2 comparison of cannabis use and psychosis, concluding that schizophrenia in cannabis users is likely due to familial risk rather than to cannabis exposure.
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;156(2–3):277–80.
Valmaggia LR, Day FL, Jones C, Bissoli S, Pugh C, Hall D, et al. Cannabis use and transition to psychosis in people at ultra-high risk. Psychol Med. 2014;44(12):2503–12.
Niemi-Pynttäri JA, Sund R, Putkonen H, Vorma H, Wahlbeck K, Pirkola SP. Substance-induced psychoses converting into schizophrenia: a register-based study of 18,478 Finnish inpatient cases. J Clin Psychiatry. 2013;74(01):e94–9. A large study that found a particularly strong tendency for cannabis-induced psychosis to later convert to schizophrenia, although cannabis-induced psychosis was relatively infrequent.
Hamilton I, Lloyd C, Hewitt C, Godfrey C. Effect of reclassification of cannabis on hospital admissions for cannabis psychosis: a time series analysis. Int J Drug Policy. 2014;25(1):151–6.
Hjorthøj CR, Fohlmann A, Larsen A-M, Gluud C, Arendt M, Nordentoft M. Specialized psychosocial treatment plus treatment as usual (TAU) versus TAU for patients with cannabis use disorder and psychosis: the CapOpus randomized trial. Psychol Med. 2013;43(07):1499–510.
Madigan K, Brennan D, Lawlor E, Turner N, Kinsella A, O’Connor JJ, et al. A multi-center, randomized controlled trial of a group psychological intervention for psychosis with comorbid cannabis dependence over the early course of illness. Schizophr Res. 2013;143(1):138–42. This well-controlled study examined the effect of an intervention designed to reduce cannabis use, and found no reduction in cannabis use and no effect on clinical outcomes.
Guilarte TR, Opler M, Pletnikov M. Is lead exposure in early life an environmental risk factor for Schizophrenia? Neurobiological connections and testable hypotheses. NeuroToxicology. 2012;33(3):560–74.
Kendler KS, Ohlsson H, Mezuk B, Sundquist K, Sundquist J. A Swedish national prospective and co-relative study of school achievement at age 16, and risk for schizophrenia, other nonaffective psychosis, and bipolar illness. Schizophr Bull. 2015;sbv103.
Gosden NP. Violence of young criminals predicts schizophrenia: a 9-year register-based followup of 15-to 19-year-old criminals. Schizophr Bull. 2005;31(3):759–68.
Anwar S, Langstrom N, Grann M, Fazel S. Is arson the crime most strongly associated with psychosis?—a national case-control study of arson risk in schizophrenia and other psychoses. Schizophr Bull. 2011;37(3):580–6.
Conflict of Interest
The authors declare that they have no competing interests.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
This article is part of the Topical Collection on Substance Use and Related Disorders
About this article
Cite this article
Ksir, C., Hart, C.L. Cannabis and Psychosis: a Critical Overview of the Relationship. Curr Psychiatry Rep 18, 12 (2016). https://doi.org/10.1007/s11920-015-0657-y