Skip to main content Accessibility help

Cannabis, schizophrenia and other non-affective psychoses: 35 years of follow-up of a population-based cohort

  • E. Manrique-Garcia (a1), S. Zammit (a2), C. Dalman (a3), T. Hemmingsson (a4), S. Andreasson (a5) and P. Allebeck (a1)...



There is now strong evidence that cannabis use increases the risk of psychoses including schizophrenia, but the relationship between cannabis and different psychotic disorders, as well as the mechanisms, are poorly known. We aimed to assess types of psychotic outcomes after use of cannabis in adolescence and variation in risk over time.


A cohort of 50 087 military conscripts with data on cannabis use in late adolescence was followed up during 35 years with regard to in-patient care for psychotic diagnoses.


Odds ratios for psychotic outcomes among frequent cannabis users compared with non-users were 3.7 [95% confidence interval (CI) 2.3–5.8] for schizophrenia, 2.2 (95% CI 1.0–4.7) for brief psychosis and 2.0 (95% CI 0.8–4.7) for other non-affective psychoses. Risk of schizophrenia declined over the decades in moderate users but much less so in frequent users. The presence of a brief psychosis did not increase risk of later schizophrenia more in cannabis users compared with non-users.


Our results confirm an increased risk of schizophrenia in a long-term perspective, although the risk declined over time in moderate users.


Corresponding author

*Address for correspondence: E. Manrique-Garcia, M.D., Karolinska Hospital, Department of Public Health, Norrbacka floor 6, S-17176 Stockholm, Sweden. (Email:


Hide All
Andréasson, S, Allebeck, P, Engström, A, Rydberg, U (1987). Cannabis and schizophrenia. A longitudinal study of Swedish conscripts. Lancet ii, 14831486.
Arendt, M, Rosenberg, R, Foldager, L, Perto, G, Munk-Jorgensen, P (2005). Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases. British Journal of Psychiatry 187, 510515.
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. BMJ 325, 12121213.
Castagnini, A, Berrios, GE (2009). Acute and transient psychotic disorders (ICD-10 F23): a review from a European perspective. European Archives of Psychiatry and Clinical Neuroscience 259, 433443.
Chen, K, Kandel, DB (1995). The natural history of drug use from adolescence to the mid-thirties in a general population sample. American Journal of Public Health 85, 4147.
David, AS, Malmberg, A, Brandt, L, Allebeck, P, Lewis, G (1997). IQ and risk for schizophrenia: a population-based cohort study. Psychological Medicine 27, 13111323.
Foti, DJ, Kotov, R, Guey, LT, Bromet, EJ (2010). Cannabis use and the course of schizophrenia: 10-year follow-up after first hospitalization. American Journal of Psychiatry 167, 987993.
Hall, W, Degenhardt, L (2004). Is there a specific ‘cannabis psychosis’? In Marihuana and Madness (ed. Castle, D. and Murray, R.), pp. 89–100. Cambridge University Press: Cambridge.
Hall, W, Degenhardt, L (2009). Adverse health effects of non-medical cannabis use. Lancet 374, 13831391.
Henquet, C, Di Forti, M, Morrison, P, Kuepper, R, Murray, RM (2008). Gene–environment interplay between cannabis and psychosis. Schizophrenia Bulletin 34, 11111121.
Hickman, M, Vickerman, P, Macleod, J, Kirkbride, J, Jones, PB (2007). Cannabis and schizophrenia: model projections of the impact of the rise in cannabis use on historical and future trends in schizophrenia in England and Wales. Addiction 102, 597606.
Johns, A (2001). Psychiatric effects of cannabis. British Journal of Psychiatry 178, 116122.
Konings, M, Henquet, C, Maharajh, HD, Hutchinson, G, Van Os, J (2008). Early exposure to cannabis and risk for psychosis in young adolescents in Trinidad. Acta Psychiatrica Scandinavica 118, 209213.
Kuepper, R, van Os, J, Lieb, R, Wittchen, HU, Hofler, M, Henquet, C (2011). Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study. British Medical Journal 342, d738.
MacCoun, R, Reuter, P (1997). Interpreting Dutch cannabis policy: reasoning by analogy in the legalization debate. Science 278, 4752.
Malmberg, A, Lewis, G, David, A, Allebeck, P (1998). Premorbid adjustment and personality in people with schizophrenia. British Journal of Psychiatry 172, 308315.
McGrath, J, Welham, J, Scott, J, Varghese, D, Degenhardt, L, Hayatbakhsh, MR, Alati, R, Williams, GM, Bor, W, Najman, JM (2010). Association between cannabis use and psychosis-related outcomes using sibling pair analysis in a cohort of young adults. Archives of General Psychiatry 67, 440447.
Moore, TH, Zammit, S, Lingford-Hughes, A, Barnes, TR, Jones, PB, Burke, M, Lewis, G (2007). Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review. Lancet 370, 319328.
Murray, RM, Morrison, PD, Henquet, C, Di Forti, M (2007). Cannabis, the mind and society: the hash realities. Nature Reviews Neuroscience 8, 885895.
Nahas, GG, Latour, C (1993). Epidemiology. In Cannabis: Physiopathology, Epidemiology, Detection (ed. Nahas, G. G. and Latour, C.), pp. 193273. CRC Press: Boca Raton, FL.
Smit, F, Bolier, L, Cuijpers, P (2004). Cannabis use and the risk of later schizophrenia: a review. Addiction 99, 425430.
Solowij, N, Grenyer, BF (2002). Are the adverse consequences of cannabis use age-dependent? Addiction 97, 10831086.
Thornicroft, G (1990). Cannabis and psychosis. Is there epidemiological evidence for an association? British Journal of Psychiatry 157, 2533.
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, 319327.
Winstock, AR, Ford, C, Witton, J (2010). Assessment and management of cannabis use disorders in primary care. BMJ 340, c1571.
Zammit, S, Allebeck, P, Andreasson, S, Lundberg, I, Lewis, G (2002). Self reported cannabis use as a risk factor for schizophrenia in Swedish conscripts of 1969: historical cohort study. British Medical Journal 325, 1199.
Zammit, S, Moore, TH, Lingford-Hughes, A, Barnes, TR, Jones, PB, Burke, M, Lewis, G (2008). Effects of cannabis use on outcomes of psychotic disorders: systematic review. British Journal of Psychiatry 193, 357363.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Psychological Medicine
  • ISSN: 0033-2917
  • EISSN: 1469-8978
  • URL: /core/journals/psychological-medicine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed