INTRODUCTION

Research on the connection between drug misuse and crime has tended to focus on either aggregated measures of drug misuse and criminal behavior or specific types of drugs and specific types of offenses. Little attention has been paid to the extent to which combinations of drug misuse might be connected to crime. This is surprising for at least two reasons. First, there has been considerable attention paid in the research literature to what is sometimes referred to as polydrug or multiple drug misuse. However, much of this discussion has focused on explaining the phenomenon of multiple drug misuse or the implications of multiple drug misuse for treatment. Second, there are a number of plausible reasons to suspect that drug use combinations might be important in explaining crime. These include direct effects, such as the potential interactive or additive effects of drug mixing on judgment or behavior, and indirect effects, such as the potential amplifying effect of involvement in drug misuse on offending.

Research that has investigated the association between specific drug types, and crime has tended to investigate the use of the specific drug type in isolation from other drugs. Many studies, for example, have investigated the association between heroin misuse and criminal behavior. However, few have investigated the association between heroin use in combination with other drugs and criminal behavior.