The impact of illicit drug supply reduction on health and social outcomes: The heroin shortage in the Australian Capital Territory

Aims: We seek to establish whether a substantial decline in the supply of heroin, as measured by indicators such as drug purity, is related to changes in drug-related health indicators such as ambulance callouts to heroin overdoses and numbers participating in methadone treatment programmes, and to changes in levels of property crime. The guiding hypothesis is that reduced supply will result in positive health and social outcomes. Design: Standard time-series methods are employed to analyse official data from local law-enforcement and heroin supply indicators and several health and social outcome indicators within the Australian Capital Territory (ACT), spanning the late 1990s to early 2002. Autoregressive moving average (ARMA) models are estimated to remove autocorrelation from these series. Cross-correlation and autoregression models are then employed to identify the best predictive models. Findings: When autocorrelation has been removed, a reduction in heroin purity predicts a large decline in heroin-related ambulance callouts and an increase in methadone treatment programme enrolments. There is little evidence of an increase in negative outcomes due to heroin users switching to other drugs. A reduction in purity also predicts declines in robbery and burglary but not in theft. Conclusion: The overall evidence indicates modest links between the declines in heroin supply and increases in positive health outcomes and decreases in crime, as predicted by a simple economic model. Due to the shortness of some of the series and consequent limitations in statistical power, these conclusions should be regarded as tentative.