In a 32-year follow-up study, the authors analyze how social circumstances during early life, childhood social participation, and school performance affect the risk of being admitted to a hospital or dying from a diagnosis closely related to drug or alcohol abuse in young adulthood. A total of 11,376 Danish males born in 1953, for whom data from birth certificates and conscription board examinations had been traced, were followed until 2002 through linkage to the Danish Psychiatric, National Patient, and Cause of Death registries. At age 12 years, 7,877 subjects completed a questionnaire on social participation and school performance. During follow-up, 12 percent of these were given a diagnosis indicating drug or alcohol abuse. Having a single mother and a working-class father were each associated with an increased risk of drug or alcohol abuse in adult life. At age 12 years, those who disliked school, scored low on a school test, or preferred to visit a youth club during leisure time showed a greater risk of adult substance abuse. These associations were slightly attenuated when adjusted for educational status at conscription. Deprived social circumstances during childhood, poor school performance in early adolescence, and attending a youth club seemed to be independent markers of substance abuse in adult life.