Measuring the public health impact of police activities on illicit drug users

There is growing recognition of the influence of physical and social environments as determinants of health among illicit drug users (Burris, Blankenship, & Donoghoe, 2004; Link & Phelan, 1995; Rhodes, 2002). As such, there have been increasing efforts to identify structural interventions that alter contextual features and thereby reduce health-related harm (Des Jarlais, 2000). However, while criminologists have spent considerable energy examining the impact of police crackdowns within illicit drug markets on crime and public order (Caulkins, Larson, & Rich, 1993; Sherman & Rogan, 1995), it is only recently that public health researchers have directed their attention to the role that drug law enforcement plays in the broader risk environment of drug users (Maher & Dixon, 1999).

Although a relatively new area of inquiry among public health researchers, a significant and growing number of studies have indicated that the application of law enforcement within drug markets can lead to harmful consequences, such as unsafe injection practices and interruptions in health service delivery (Aitken, Moore, Higgs, Kelsall, & Kerger, 2002; Maher & Dixon, 1999; May & Hough, 2001; Rhodes et al., 2003; Sergeev, Karpets, Sarang, & Tikhonov, 2003; Wood et al., 2003). In light of these findings, the continued application of police crackdowns has become increasingly controversial. However, in both developed and developing countries, the vast majority of public resources used to address problems associated with illicit drug continue to be accounted for by enforcement initiatives (Drucker, 1999; Wodak, Ali, & Farrell, 2004).

In this issue of the International Journal of Drug Policy, Hannah Cooper and colleagues have joined the growing number of researchers who have turned their attention towards examining the impact of law enforcement activities on the health of illicit drug users. In this ecological study, however, the investigators indicated that, following a series of police crackdowns, there was no change, and potentially even a decline in hospitalisations stemming from abscesses, endocarditis, and cellulitis, once rates of incarceration and other confounders were considered. These findings, despite being derived from a rigorous approach, stand in contrast with earlier studies, which have suggested that risk factors for bacterial infections increase when police activities are scaled-up (Aitken et al., 2002; Maher & Dixon, 1999).

There are, however, several limitations inherent in ecological study designs that may explain this incongruence, such as the inability to account for potential confounders. In the Cooper et al. study, several factors such as displacement of drug users and changes in health seeking behaviour, could not be fully accounted for, and we therefore agree with the authors that there is a need for much further study in this area. As well, the authors also rightly note the difficulties in accurately measuring the downstream impacts of the police crackdown, including measurement of the number of injection-related illnesses among prisoners who may have been arrested during the crackdown. This highlights a significant challenge facing researchers who seek to evaluate more distal effects of policing initiatives. The judicial process is, in most settings, long and complex, and the impacts of enforcement activities occurring at the street level can reverberate in an array of settings, such as prisons and pre-trial detention centres (Drucker, 1999). These settings will be key contexts to consider given existing evidence of high risk injecting practices occurring in them (Darke, Kaye, & Finlay-Jones, 1998; Malliori et al., 1998).

Drug law enforcement remains the dominant approach to drug policy despite a lack of sound scientific confirmation of its benefit in terms of supply reduction, and increasing evidence of its harmful impacts. The continued investigation of the health consequences of drug law enforcement is therefore of great importance. However, as this area of inquiry grows, new methodological challenges will be encountered, including the challenge of considering the effects of enforcement throughout the justice system and after displacement has occurred. This work, however, will ultimately be critical in elucidating and documenting the full public health impacts of what remains the dominant approach to addressing drug-related harm globally.