Given the absence of relations between several ECFs with early risk behaviors and the weak relation of working memory and reversal learning in comparison with impulsivity, it is important to ask why these measures of ECF correlate with drug use more strongly in adults (Bechara & Martin, 2004) or youth with more serious substance use disorders (Tarter et al., 2003). One possibility is that as youth experience increased drug use, ECFs become compromised so that their performance deteriorates. There is evidence that heavy use of potentially addictive drugs alters brain function producing deficits in working memory and inhibitory control (Jentsch & Taylor, 1999). Over time, these effects could introduce correlations between ECFs and drug use. For example, the finding that ECF did not correlate with drug use at ages 12 to 15 (Nigg et al., 2004) but did at ages 15 to 17 (Nigg et al., 2006) is consistent with such an account.
