Second, teacher reports on the Children’s Problem Checklist (CPC; Healey, Miller, Castelli, Marks, & Halperin, 2008) were used to assess impairment related to ADHD using six items (disrupts classroom, difficulty getting along with children at school, difficulty making or keeping friends, difficulty getting along with teachers and/or other adults, feeling bad about him/herself, and having many accidents). Each item was rated on a 4-point scale (no, mild, moderate, or severe problems). Internal consistency in the normative sample was .70 and stability at 6-month follow-up was .69 (Healey et al., 2008). In this sample, Cronbach’s alphas at BL, F1, F2, and F3 were .87, .80, .85, and .85, respectively.
