DSM-IV antisocial personality disorder diagnosis requires that conduct disorder be exhibited before age 15. However, recent studies have reported on men and women without conduct disorder before age 15 but qualified for the adulthood antisocial personality criterion (AAB). This general-population, retrospective study investigated the plausibility of causal relationships between adolescent drug and alcohol misuse (ADAM) and AAB among subgroups who reported childhood-onset conduct problems (CP), adolescent-onset CP, or no more than one conduct problem. Data from the Epidemiological Catchment Area Study (N = 8,724) suggested that persons with childhood-onset CP are at much greater risk for AAB than persons with adolescent-onset CP. Nevertheless, large proportions of men and women with AAB had adolescent-onset CP or no CP. Regardless of CP history, being drunk by age 18 or having a drug use-related symptom before age 18 increased AAB risk, even after controlling for having a substance use-related disorder in adulthood. Mechanisms that potentially explain these associations are discussed.