Psychiatric predictors of adolescent and young adult drug use and abuse: what have we learned?

First, the link between conduct disorder and drug use nd abuse is confirmed in great detail. Evidence is presented ross-sectionally (Roberts) and prospectively (Cohen, Costello, ibbons, Fergusson, Pardini, Wittchen), for conduct disorder as strong predictor of the use and abuse of tobacco (Fergusson), lcohol (Costello Fergusson, Pardini), cannabis (Cohen, Ferguson, Wittchen), and other illicit drugs (Fergusson) across the age ange from age 7 to adulthood. The wealth of prospective data resented here does away with any concerns about order effects: onduct problems precede drug use and abuse. This set of findings, however familiar they may be to many eaders of this journal, has important implications for the orgaization of research into prevention and treatment. If we accept he argument that prevention needs to target risk factors as early s possible (Mrazek and Haggerty, 1994), then drug prevenion policy-makers need to consider the evidence that very early pre-school) intervention may be the most cost-effective way of reventing conduct problems (Tremblay et al., 1995, 1992). It ollows that the best way to prevent drug abuse may be early ntervention to prevent conduct problems (Ialongo et al., 1999; torr et al., 2002). However, the papers in this issue also show that the relationhip between conduct disorder (CD) and substance use disorders SUD) changes with developmental stage, with sex, and possibly lso with race/ethnicity. The younger the sample, the stronger the rediction from CD to SUD (Gibbons). In Fergusson’s 17–25ear-olds, early CD did not predict alcohol use, but it did predict buse/dependence, as well as use of cannabis and other illicit rugs. This is consistent with an earlier paper in this journal howing that the effect of CD on onset of drug use was strongest t age 13 and “faded” after about age 16 (Sung et al., 2004). This eads to a question that cannot be answered by most of these data ets as the subjects are too young: if conduct disorder predicts y s b t