The Global Burden of Disease projects: what have we learned about illicit drug use and dependence and their contribution to the global burden of disease?

INTRODUCTION: The Global Burden of Disease (GBD) 2010 study updated the findings of earlier exercises. It provided regional and global estimates of the burden of disease attributable to diseases, injuries and risk factors. Here we provide a brief summary of the work for illicit drug use.
DESIGN: Systematic reviews were undertaken to estimate the major epidemiological parameters (incidence, prevalence, duration/remission and mortality) for each drug. Reviews evaluated the nature and quality of evidence for illicit drug use as a risk factor for many health outcomes, for the comparative risk assessment (CRA) exercise.
RESULTS: Substantial gaps existed in basic epidemiological parameters. Following modelling and imputation of missing data, it was estimated that opioid and amphetamine dependence were the most common forms of illicit drug dependence in 2010; opioid dependence was responsible for the greatest burden. Few putative consequences of illicit drug use had the quality or quantity of data required to be included in the CRA. DISCUSSION: Estimates of the extent and distribution of disease burden are likely to shape global and regional health policy development. The GBD exercise will be repeated on an annual basis; GBD 2010 clearly demonstrated that although the illicit drug field is generating more and better epidemiological data on the health risks of drug use, there is still much work to be done to generate defensible estimates of the magnitude of risk, particularly for impactful and prevalent outcomes, such as injuries, violence and mental health complications. Until then, burden of disease attributable to illicit drugs will be underestimated.