This article examines relationships between psychiatric disorder, poor school performance, family dysfunction and low family income in a cohort of 8-12-year-olds and use of tobacco, marijuana and hard drugs 4 years later. Conduct disorder assessed by teachers predicted use of alcohol and hard drugs, while low family income and poor school performance predicted use of tobacco. Neither attention-deficit disorder nor emotional disorder was related to adolescent substance use. Although behavioural deviance in childhood is associated with adolescent substance use, it has limited potential for identifying groups at risk in the general population for purposes of preventing substance use in later years.