et al., 2006; Shaw et al., 2007). Although of lesser magnitude, within that same group, greater ADHD severity at 5–6 years was associated with poorer neuropsychological functioning at 6–7 years, suggesting that entry into formal school may be the time that the association between neuropsychological functioning and ADHD severity becomes reciprocal, possibly leading to worse outcomes. This latter association between ADHD severity at 5–6 years and neuropsychological functioning a year later was also observed in TD children, suggesting that even modest expressions of ADHD among TD children might portend poorer neuropsychological functioning a year later. There were no associations between changes in neuropsychological functioning and later ADHD severity among TD children. This may be due to their consistently low and less variable levels of behavioral difficulties (see Table 1), as well as their greater temporal stability (see Figure 2B), which may have impeded the ability to test the impact of changes over time.
