Journal article
Cannabis use and risk of schizophrenia: a Mendelian randomization study.
- Abstract:
- Cannabis use is observationally associated with an increased risk of schizophrenia, but whether the relationship is causal is not known. Using a genetic approach, we took 10 independent genetic variants previously identified to associate with cannabis use in 32 330 individuals to determine the nature of the association between cannabis use and risk of schizophrenia. Genetic variants were employed as instruments to recapitulate a randomized controlled trial involving two groups (cannabis users vs nonusers) to estimate the causal effect of cannabis use on risk of schizophrenia in 34 241 cases and 45 604 controls from predominantly European descent. Genetically-derived estimates were compared with a meta-analysis of observational studies reporting ever use of cannabis and risk of schizophrenia or related disorders. Based on the genetic approach, use of cannabis was associated with increased risk of schizophrenia (odds ratio (OR) of schizophrenia for users vs nonusers of cannabis: 1.37; 95% confidence interval (CI), 1.09-1.67; P-value=0.007). The corresponding estimate from observational analysis was 1.43 (95% CI, 1.19-1.67; P-value for heterogeneity =0.76). The genetic markers did not show evidence of pleiotropic effects and accounting for tobacco exposure did not alter the association (OR of schizophrenia for users vs nonusers of cannabis, adjusted for ever vs never smoker: 1.41; 95% CI, 1.09-1.83). This adds to the substantial evidence base that has previously identified cannabis use to associate with increased risk of schizophrenia, by suggesting that the relationship is causal. Such robust evidence may inform public health messages about cannabis use, especially regarding its potential mental health consequences.Molecular Psychiatry advance online publication, 24 January 2017; doi:10.1038/mp.2016.252.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
Actions
Authors
- Publisher:
- Nature Publishing Group
- Journal:
- Molecular Psychiatry More from this journal
- Publication date:
- 2017-01-01
- Acceptance date:
- 2016-11-28
- DOI:
- EISSN:
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1476-5578
- ISSN:
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1359-4184
- Language:
-
English
- Keywords:
- Pubs id:
-
pubs:673349
- UUID:
-
uuid:b6368ab8-7f1b-4907-9a81-e77f5056e338
- Local pid:
-
pubs:673349
- Source identifiers:
-
673349
- Deposit date:
-
2017-04-12
Terms of use
- Copyright holder:
- Holmes et al
- Copyright date:
- 2017
- Notes:
- © The Author(s) 2017. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
- Licence:
- CC Attribution (CC BY)
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