In addition to these two explanations, it is also possible that early manifestations of risk for SUD and conduct disorder are mere markers for a developmental path that unfolds whether preadolescents use drugs or not. For example, Prescott, Aggen, & Kendler (1999) find using twin data that early use of alcohol does not add increased risk of later alcohol dependence above the effects of genetic predispositions to alcohol abuse. Other genetically-informed research also suggests that early substance use is more environmentally driven while later emergence of dependence and problems with drugs is more under the influence of genes (McGue et al., 2006; Pagan et al., 2006). From this perspective, discouraging early use of drugs and other risky behavior may not be the best strategy; instead interventions that enhance the control of underlying impulsive tendencies may be more successful in reducing the development of risk-behavior trajectories.
