In these more stringent analyses within discordant twin pairs, the risk for SA among those reporting EAU was elevated nearly four-fold even after controlling for other potentially causal influences (e.g., childhood sexual abuse, other substance use). This elevated risk for SA among twins who reported drinking prior to age 15 could reflect individual specific factors that precede EAU, such as other traumatic childhood events or different peer groups that facilitate risky behavior. For example, Trucco and colleagues (2011) found that peer delinquency prospectively predicts peer approval of alcohol and peer use, which in turn predicted initiation of alcohol use among adolescents. Delinquency during adolescence has been linked to a number of maladaptive outcomes, including less positive parenting (Trucco et al. 2011), and furthermore, lack of perceived familial support has been associated with SA (Miller et al. 2015;Wolff et al. 2013). Therefore, these unshared individual-specific influences may be critical in understanding the link between EAU and SA. However, these findings also support the possibility of a causal pathway from EAU to SA. This is consistent with epidemiological research in multiple countries
