Association between cannabis and psychiatric hospitalization
Article first published online: 28 DEC 2010
© 2010 John Wiley & Sons A/S
Acta Psychiatrica Scandinavica
Volume 123, Issue 5, pages 368–375, May 2011
How to Cite
Schubart, C. D., Boks, M. P. M., Breetvelt, E. J., van Gastel, W. A., Groenwold, R. H. H., Ophoff, R. A., Sommer, I. E. C. and Kahn, R. S. (2011), Association between cannabis and psychiatric hospitalization. Acta Psychiatrica Scandinavica, 123: 368–375. doi: 10.1111/j.1600-0447.2010.01640.x
- Issue published online: 14 APR 2011
- Article first published online: 28 DEC 2010
- Accepted for publication October 27, 2010
- mental health
Schubart CD, Boks MPM, Breetvelt EJ, van Gastel WA, Groenwold RHH, Ophoff RA, Sommer IEC, Kahn RS. Association between cannabis and psychiatric hospitalization.
Objective: To investigate the relationship between cannabis use and mental health.
Method: A cross-sectional analysis in a sample of 17 698 individuals with a mean age of 22 years (SD: 4.2). Participants provided information on the amount and initial age of cannabis use and history of psychiatric hospitalizations through a web-based questionnaire. To quantify Δ9-tetrahydrocannabinol exposure, we operationalized cannabis use as the amount of money spent on cannabis per week over the last month. The odds ratio of having a history of psychiatric hospitalizations was the primary outcome measure.
Results: We found a dose–response relationship between the amount of cannabis use and the odds for psychiatric hospitalization. Adjusted odds ratios for hospitalization increased with the amount of cannabis consumed from 1.6 (95% CI: 1.1–2.3) in incidental users to 6.2 (95% CI: 4.3–8.9) in heavy users (>€25/week). Our data suggested that concomitant drug use was an intermediate factor. Exposure to cannabis before the age of 12 years was found to carry a 4.8 (95% CI: 2.9–7.8) times increased odds for past psychiatric hospitalizations.
Conclusion: We conclude that early and heavy uses of cannabis are each and independently associated with poor mental health in its users.