Cannabis as a causal factor for psychosis — a review of the evidence

  • John Witton
  • Louise Arseneault
  • Mary Cannon
  • Robin Murray


Adults suffering from psychosis have high rates of cannabis use. However, there remains controversy as to whether this is a cause or consequence of the psychosis. This review tests the hypothesis that cannabis can cause psychosis by reviewing studies verifying three important criteria for causality in psychiatry: association, temporal priority, and direction, with the emphasis put on prospective longitudinal population-based studies that tested temporal priority. Evidence supports a causal role for cannabis in the development of psychosis but it appears that cannabis use is neither a sufficient nor a necessary cause for psychosis. Rather, it is a component cause - part of a complex constellation of factors leading to psychosis. On an individual level, cannabis use appears to confer only a two-to three-fold increase in the relative risk for later schizophrenia. On a population level, elimination of cannabis use could lead to a 7-13% reduction in incidence of schizophrenia. Thus, some cases of psychotic disorder could be prevented by discouraging cannabis use, particularly among vulnerable youths. More research is needed to better understand the mechanisms by which cannabis causes psychosis.


Psychotic Symptom Cannabis User Population Attributable Fraction Psychotic Experience Temporal Priority 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. American Psychiatric Association (1994) Diagnostic and Statistical Manual of Mental Disorders (4th edn) (DSM-IV). American Psychiatric Association, Washington, DCGoogle Scholar
  2. Andréasson S, Allebeck P, Engström A, Rydberg U (1987) Cannabis and schizophrenia: a longitudinal study of Swedish conscripts. Lancet 11:1483–1485CrossRefGoogle Scholar
  3. Arseneault L, Cannon M, Poulton R, Murray R, Caspi A, Moffitt TE (2002) Cannabis use in adolescence and risk for adult psychosis: longitudinal prospective study. British Medical Journal 325:1212–1213PubMedCrossRefGoogle Scholar
  4. Cannon M, Caspi A, Moffitt TE, Harrington H, Taylor A, Murray RE, Poulton R (2002) Evidence for early, specific, pan-developmental impairment in schizophreniform disorder: results from a longitudinal birth cohort. Archives of General Psychiatry 59:449–457PubMedCrossRefGoogle Scholar
  5. Cannon M, Jones P, Gilvarry C, Rifkin L, McKenzie K, Foerster A, Murray RM (1997) Premorbid social functioning in schizophrenia and bipolar disorder: similarities and differences. American Journal of Psychiatry 154:1544–1550PubMedGoogle Scholar
  6. Cantwell R, Brewin J, Glazebrook C, Dalkin T, Fox R, Medley I, Harrison G (1999) Prevalence of substance abuse in first-episode psychosis. British Journal of Psychiatry 174:150–153PubMedCrossRefGoogle Scholar
  7. Degenhardt L (2003) The link between cannabis use and psychosis: furthering the debate. Psychological Medicine 33:3–6PubMedCrossRefGoogle Scholar
  8. Degenhardt L, Hall W, Lynskey M et al (2004) The association between cannabis use and depression: a review of the evidence. In: Castle DJ, Murray R (eds) Marijuana and Madness. Cambridge University Press, Cambridge, UK (in press)Google Scholar
  9. Duke PJ, Pantelis C, McPhillips MA, Barnes TRE (2001) Comorbid non-alcohol substance misuse among people with schizophrenia. British Journal of Psychiatry 179:509–513PubMedCrossRefGoogle Scholar
  10. Farrell M, Howes S, Taylor C, Lewis G, Jenkins R, Bebbington P, Jarvis M, Brugha T, Gill B, Meltzer H (1998) Substance misuse and psychiatric comorbidity: an overview of the OPCS National Psychiatric Comorbidity Survey. Addictive Behavior 23:909–918CrossRefGoogle Scholar
  11. Fergusson DM, Horwood LJ (2000) Does cannabis use encourage other forms of illicit drug use? Addiction 95:505–520PubMedCrossRefGoogle Scholar
  12. Fergusson DM, Horwood LJ, Swain-Campbell NR (2003) Cannabis dependence and psychotic symptoms in young people. Psychological Medicine 33:15–21PubMedGoogle Scholar
  13. Grech A, Takei N, Murray R (1998) Comparison of cannabis use in psychotic patients and controls in London and Malta. Schizophrenia Research 29:22CrossRefGoogle Scholar
  14. Hall W, Degenhardt L (2002) Cannabis use and psychosis: a review of clinical and epidemiological evidence. Australian and New Zealand Journal of Psychiatry 34:26–34CrossRefGoogle Scholar
  15. Hall W, Degenhardt L (2004) Is there a specific “cannabis psychosis”? In: Castle DJ, Murray R (eds) Marijuana and Madness. Cambridge University Press, Cambridge, UK (in press)Google Scholar
  16. Hambrecht M, Häfner H (1996) Substance abuse and the onset of schizophrenia. Biological Psychiatry 40:1155–1163PubMedCrossRefGoogle Scholar
  17. Hill AB (1965) The environment and disease: association or causation? Proceedings of the Royal Society of Medicine 58:295–300PubMedGoogle Scholar
  18. Johns A (2001) Psychiatric effects of cannabis. British Journal of Psychiatry 178:116–122PubMedCrossRefGoogle Scholar
  19. Johnston LD, O’Malley PM, Bachman JG (2001) Monitoring the Future national results on adolescent drug use: overview of key findings (NIH Publication No. 025105). National Institute on Drug Abuse, Bethesda, MDGoogle Scholar
  20. Jones P, Rodgers B, Murray R, Marmot M (1994) Child developmental risk factors for adult schizophrenia in the British 1946 birth cohort. Lancet 344:1398–1402PubMedCrossRefGoogle Scholar
  21. Kazuo Y, Kandel DB (1984) Patterns of drug use from adolescence to young adult-hood: II. sequences of progression. American Journal of Public Health 74:668–672CrossRefGoogle Scholar
  22. Malmberg A, Lewis G, David A, Allebeck P (1998) Premorbid adjustment and per-sonality in people with schizophrenia. British Journal of Psychiatry 172:308–313PubMedCrossRefGoogle Scholar
  23. Mathers DC, Ghodse AH (1992) Cannabis and psychotic illness. British Journal of Psychiatry 161:648–653PubMedCrossRefGoogle Scholar
  24. McCreadie RG (2002) Use of drugs, alcohol and tobacco by people with schizophrenia: case-control study. British Journal of Psychiatry 181:321–323PubMedCrossRefGoogle Scholar
  25. McGuire PK, Jones P, Harvey I, Williams M, MacGuffin P, Murray RM (1995) Morbid risk of schizophrenia for relatives of patients with cannabis-associated psychosis. Schizophrenia Research 15:277–281PubMedCrossRefGoogle Scholar
  26. Menezes PR, Johnson S, Thornicroft G, Marshall J, Prosser D, Bebbington P, Kuipers E (1996) Drug and alcohol problems among individuals with severe mental illnesses in South London. British Journal of Psychiatry 168:612–619PubMedCrossRefGoogle Scholar
  27. Miller P, Lawrie SM, Hodges A, Clafferty R, Cosway R, Johnstone CE (2001) Genetic liability, illicit drug use, life stress and psychotic symptoms: preliminary findings from the Edinburgh study of people at high risk for schizophrenia. Social Psychiatry and Psychiatric Epidemiology 36:338–342PubMedCrossRefGoogle Scholar
  28. Murray R, Grech A, Phillips P et al (2003) What is the relationship between substance abuse and schizophrenia? In: Murray R, Jones P, Susser E, Van Os J, Cannon M (eds) The Epidemiology of Schizophrenia. Cambridge University Press, Cambridge, UK (in press)Google Scholar
  29. Negrete JC, Knapp WP, Douglas D, Bruce Smith W (1986) Cannabis affects the severity of schizophrenia symptoms: results of a clinical survey. Psychological Medicine 16:515–520PubMedCrossRefGoogle Scholar
  30. Patton GC, Coffrey C, Carlin JB, Degenhardt L, Lynskey M, Hall W (2002) Cannabis use and mental health in young people: cohort study. British Medical Journal 325:1195–1198PubMedCrossRefGoogle Scholar
  31. Phillips LJ, Curry C, Yung AR, Yuen HP, Adlard S, McGorry S (2002) Cannabis use is not associated with the development of psychosis in an `ultra’ high-risk group. Australian and New Zealand Journal of Psychiatry 36:800–806PubMedCrossRefGoogle Scholar
  32. Poulton R, Caspi A, Moffitt TE, Cannon M, Murray R, Harrington H (2000) Children’s self-reported psychotic symptoms and adult schizophreniform disorder: a 15-year longitudinal study. Archives of General Psychiatry 57:1053–1058PubMedCrossRefGoogle Scholar
  33. Regier D, Farmer ME, Rae DS, Locke BZ, Keith SJ, Judd LL, Goodwin FK (1990) Comorbidity of mental disorders with alcohol and other drug abuse: results from the epidemiologic catchment area (ECA) study. Journal of the American Medical Association 264:2511–2518PubMedCrossRefGoogle Scholar
  34. Robins LN, Regier DA (1991) Psychiatric Disorders in America: The Epidemiologic Catchment Area Study. The Free Press, New YorkGoogle Scholar
  35. Rothman KJ, Greenland S (eds) (1998) Modern epidemiology, second edition. Lippincott-Raven, PhiladelphiaGoogle Scholar
  36. Silva PA, Stanton WR (eds) (1996) From Child to Adult: The Dunedin Multidisciplinary Health and Development Study. Oxford University Press, AucklandGoogle Scholar
  37. Susser M (1991) What is a cause and how do we know one? A grammar for prag-matic epidemiology. American Journal of Epidemiology 133:635–648PubMedGoogle Scholar
  38. Thornicroft G (1990) Cannabis and psychosis. British Journal of Psychiatry 157:25–33PubMedCrossRefGoogle Scholar
  39. Tien AY, Anthony JC (1990) Epidemiological analysis of alcohol and drug use as risk factors for psychotic experiences. Journal of Nervous and Mental Disease 178:473–480PubMedGoogle Scholar
  40. Van Os J, Bak M, Hanssen M, Bijl RV, De Graaf R, Verdoux H (2002) Cannabis use and psychosis: a longitudinal population-based study. American Journal of Epidemiology 156:319–327PubMedCrossRefGoogle Scholar
  41. Verdoux H (2004) Cannabis and psychosis proneness. In: Castle DJ, Murray R (eds) Marijuana and Madness. Cambridge University Press, Cambridge, UK (in press)Google Scholar
  42. Verdoux H, Gindre C, Sorbara F, Tournier M, Swendson JD (2003) Effects of cannabis and psychosis vulnerability in daily life: an experience sampling test study. Psychological Medicine 33:23–32PubMedCrossRefGoogle Scholar
  43. Wheatley M (1998) The prevalence and relevance of substance use in detained schizophrenic patients. Journal of Forensic Psychiatry 9:114–129CrossRefGoogle Scholar
  44. Zammit S, Allebeck P, Andréasson S, Lundberg I, Lewis G (2002) Self-reported cannabis use as a risk factor for schizophrenia: further analysis of the 1969 Swedish conscript cohort. British Medical Journal 325:1199–1201PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • John Witton
    • 1
  • Louise Arseneault
    • 2
  • Mary Cannon
    • 3
  • Robin Murray
    • 3
  1. 1.National Addiction Centre, Institute of PsychiatryKing’s College LondonUK
  2. 2.Social, Genetic, and Developmental Psychiatry Research Centre, Institute of PsychiatryKing’s College LondonUK
  3. 3.Division of Psychological Medicine, Institute of PsychiatryKing’s College LondonUK

Personalised recommendations