The three postulated causal relationships that have been suggested in the literature hold that drug use leads to crime, crime leads to drug use, and drug use and crime are both manifestations of a general orientation toward deviance or delinquency. This review focuses on studies of officially defined drug users and delinquents and studies involving normal youth populations. Issues that remain problematic and should have high priority for future research include drug use and delinquent behavior, delinquency preceding drug use, delinquency level after onset of drug use, causal models of drug use and delinquency, and drug use-delinquency relationships for specific drugs. 30 references