Combined effects of law enforcement and substitution treatment on heroin mortality

To explore the combined effects of street-level law enforcement and substitution treatment programs on drug-related mortality, taking into account prevalence of heroin use and changes in injecting behaviour.

Time trend analysis using annual police reports and case register data of opioid substitution treatments in Switzerland, 1975-2007.

Drug-related mortality increased during times of more intense street-level law enforcement [odds ratio (OR) 1.32, 95% confidence interval (95% CI) 1.15-1.51], and the number of drug-related deaths predicted the number of heroin possession offences 2 years later (r = 0.97, P < 0.001). Substitution treatment had a protective effect on drug-related mortality (OR 0.23, 95% CI 0.18-0.30). Surprisingly, the number of drug-related deaths was substantially biased by an oscillation period of 14 years (OR 1.24, 95% CI 1.17-1.32).

Our analysis revealed that the amount of police resources allocated to law enforcement was determined rationally, however, on biased grounds and with untoward consequences. Substitution treatment of heroin users reduced drug-related mortality in the long run, but different factors masked its impact for several years. Therefore, the introduction-or the expansion-of opioid substitution treatment programs should not be promoted with the argument of an immediate reduction of drug-related deaths in a country.