DRUG-ABUSE AND DEPENDENCE

3258 randomly selected adult household residents of Edmonton were inte rviewed by trained lay interviewers using the Diagnostic Interview Sch edule (DIS). The lifetime prevalence of drug abuse/dependence was 6.9% , with a male:female ratio of 3:1. The most commonly used drug was can nabis followed by amphetamines, opiates, barbiturates, hallucinogens a nd cocaine. 80.3% of those with drug abuse/dependence also had a lifet ime diagnosis of another psychiatric disorder. In those with a comorbi d diagnosis, the mean age of onset for the other psychiatric disorder was generally found to be younger than for the onset of drug abuse/dep endence. Different comorbid disorders were found to significantly affe ct patterns of drug use.