The significant association between adolescent substance use and involvement in delinquent or criminal activity has been firmly established in existing literature. In two previous surveys of young people in detention in New South Wales, Australia, 1989 and 1994, patterns of alcohol and other drug use appeared to have been reasonably stable. This study is a replication of those two surveys. Structured interviews were conducted on 300 adolescent participants in detention in NSW. They were predominantly male (90 percent) with an average age of 16.5 and an over-representation of Aboriginal and Torres Straits Islander peoples. The participants had a similar demographic profile to previous samples of this population. In the decade 1989-1999, the patterns of lifetime alcohol and tobacco use were stable, with increases in amphetamine, opioid, and cocaine use since 1994. However, a significant decrease was seen in the frequent use of alcohol. In summary, a retrospective diagnosis of conduct disorder obtained prior to the initiation of heroin use was associated with a range of problems that had continued to occur into adult life. These patients were at higher risk of attempted suicide, as well as at a higher risk within the treatment setting. A history of conduct disorder increased the risk of attempted suicide over and above the higher risks associated with injecting drug use. 29 References