Several interesting differences emerged when comparing the hierarchical model of behavioral disinhibition at age 12 with the model at age 17. First, we note that at age 12, the latent behavioral disinhibition factor was more heavily weighted by ADHD and conduct problems and less related to early substance use, even though the factor loadings for all of the component measures were significant. This finding may be expected, given that the onset of both ADHD and conduct disorder symptoms typically predates the onset of substance use (Elkins, McGue, & Iacono, 2007; Loeber, Stouthamer-Loeber, & White, 1999; Young et al., 1995). At age 17, the loadings were generally higher (with the exception of ADHD), ranging from .36 for novelty seeking to .86 for conduct disorder, and were more comparable across the measures. Substance use, in particular, was more involved in the latent construct at age 17 (λ = .47) than at age 12 (λ = .15). We note that lifetime symptom counts and substance use measures were used at both time points, dictating that individual scores either remained unchanged or increased over
