The global epidemiology and contribution of cannabis use and dependence to the global burden of disease: results from the GBD 2010 study

PLoS One. 2013 Oct 24;8(10):e76635. doi: 10.1371/journal.pone.0076635. eCollection 2013.

Abstract

Aims: Estimate the prevalence of cannabis dependence and its contribution to the global burden of disease.

Methods: Systematic reviews of epidemiological data on cannabis dependence (1990-2008) were conducted in line with PRISMA and meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Culling and data extraction followed protocols, with cross-checking and consistency checks. DisMod-MR, the latest version of generic disease modelling system, redesigned as a Bayesian meta-regression tool, imputed prevalence by age, year and sex for 187 countries and 21 regions. The disability weight associated with cannabis dependence was estimated through population surveys and multiplied by prevalence data to calculate the years of life lived with disability (YLDs) and disability-adjusted life years (DALYs). YLDs and DALYs attributed to regular cannabis use as a risk factor for schizophrenia were also estimated.

Results: There were an estimated 13.1 million cannabis dependent people globally in 2010 (point prevalence0.19% (95% uncertainty: 0.17-0.21%)). Prevalence peaked between 20-24 yrs, was higher in males (0.23% (0.2-0.27%)) than females (0.14% (0.12-0.16%)) and in high income regions. Cannabis dependence accounted for 2 million DALYs globally (0.08%; 0.05-0.12%) in 2010; a 22% increase in crude DALYs since 1990 largely due to population growth. Countries with statistically higher age-standardised DALY rates included the United States, Canada, Australia, New Zealand and Western European countries such as the United Kingdom; those with lower DALY rates were from Sub-Saharan Africa-West and Latin America. Regular cannabis use as a risk factor for schizophrenia accounted for an estimated 7,000 DALYs globally.

Conclusion: Cannabis dependence is a disorder primarily experienced by young adults, especially in higher income countries. It has not been shown to increase mortality as opioid and other forms of illicit drug dependence do. Our estimates suggest that cannabis use as a risk factor for schizophrenia is not a major contributor to population-level disease burden.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Age Factors
  • Cannabis / adverse effects*
  • Comorbidity
  • Disabled Persons / statistics & numerical data
  • Female
  • Geography, Medical
  • Global Health / statistics & numerical data*
  • Humans
  • Male
  • Marijuana Abuse / epidemiology*
  • Prevalence
  • Risk Factors
  • Schizophrenia / epidemiology
  • Schizophrenia / etiology
  • Sex Factors

Grant support

Louisa Degenhardt is supported by an Australian National Health and Medical Research Council (NHMRC) Principal Research Fellowship. Wayne Hall is funded by an NHMRC Australia Fellowship. The National Drug and Alcohol Research Centre at the University of NSW is supported by funding from the Australian Government under the Substance Misuse Prevention and Service Improvements Grants Fund. Harvey A Whiteford and Alize J Ferrari are affiliated with the Queensland Centre for Mental Health Research, which receives its core funding from the Queensland Department of Health. Abraham D Flaxman, Theo Vos, Rebecca Engell, Greg Freedman and Christopher JL Murray received funding for their work on the Global Burden of Disease 2010 Study from the Bill and Melinda Gates Foundation. No funding bodies had any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.