Chunk #48 — Discussion — Structure and Etiology of Behavioral Disinhibition Components Across Adolescence — Individual components of behavioral disinhibition
First, the heritability of substance use was substantially higher in early adolescence, demonstrating that while genes are still influencing substance use in late adolescence, there is a substantial increase in the shared environmental component of the variance in substance use from early to late adolescence. These results are consistent with previous studies suggesting that while early exposure to substances is moderately heritable (Legrand, McGue, & Iacono, 1999), later adolescent experimentation is mostly influenced by environmental factors (Hopfer, Crowley, & Hewitt, 2003). However, persistent substance use leading to abuse and dependence problems has been clearly shown to have a strong genetic etiology (Koopmans, Slutske, Heath, Neale, & Boomsma, 1999; Rhee et al., 2003; Rose, Dick, Viken, Pulkkinen, & Kaprio, 2001; Young, Rhee, Stallings, Corley, & Hewitt, 2006).
