An additional SEM model was run to test whether medication treatment was a potential confounder for the longitudinal relations between neuropsychological functioning and ADHD severity observed among H/I children. Two dichotomous variables (medication treatment at F1 and at F2) were included. Paths were tested from medication treatment at F1 leading up to both ADHD severity and neuropsychological functioning at F2; and from medication treatment at F2 to ADHD severity and neuropsychological functioning at F3. This model showed acceptable fit [Chi square (df) =404.97(284); p<.001; χ2/df ratio= 1.43; CFI=.92; RMSEA=.05]. While F1 ADHD severity was associated with greater likelihood of F2 medication treatment (β=.24; p<.01), and medication treatment at F1 was associated with medication treatment at F2 (β=.50; p<.001), no other paths from or to medication treatment were significant. Other paths in the model were consistent with what was observed in the model without medication treatment.
