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  • Print publication year: 2011
  • Online publication date: November 2011

12 - Which cannabis users develop psychosis?


This chapter explores the policy implications of the evidence on cannabis and psychosis for mental health services, health education about the risks of cannabis use, and public policy toward recreational cannabis use. It is useful to compare the strength of the evidence on cannabis and psychosis with that of observational evidence on relationships between adverse health effects and other types of drug use. These comparisons facilitate more consistent, even-handed appraisals of the comparative strengths and weakness of evidence on the adverse effects of different drugs. Providing credible advice to young people on the mental health risks of cannabis use is complicated by the polarized views on the health risks of cannabis expressed in the larger cannabis policy debate. It seems likely that governments in most developed countries will continue to prohibit cannabis use by adults, regardless of whether they do so by imposing criminal or civil penalties for use.

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