Anne Fleur Kortekaas-Rijlaarsdam

21 INTRODUCTION 1 four mental health clinics in the Netherlands, the Dutch parent association for children with developmental problems, and the study’s website. Eligible participants were Dutch- speaking children, aged between 8 and 13 years, with a primary clinical DSM-IV-TR diagnosis of ADHD, an estimated IQ>70, and no diagnosis of autism spectrum disorder or neurological disorders. TD children were recruited in the same period through primary schools throughout the Netherlands. Inclusion criteria for the TD group were comparable to those in the ADHD group, except for the absence of a diagnosis of ADHD. The direct effects of long-acting MPH (Equasym XL®) on academic performance were compared to placebo using a randomized double-blind placebo-controlled cross-over design. Equasym XL ® has an 8-hr duration of action with a 30% component of immediate release and a 70% component of extended release 4-5 hours after dosing (Banaschewski et al., 2006). Children were included after successful titration by their treating physician. Treatment duration was seven days with a 48 hour washout before and in between the treatment weeks. Figure 1.3 shows the set-up for the RCT and experimental studies described in Chapters 5 and 6. Academic functioning was assessed using a set of standardized tests for math, reading and spelling, as well as actual classroom tasks (mathematical word problems developed by the Dutch pupil monitoring system). Behavioral functioning was assessed with parent- and teacher questionnaires. Cognition was assessed using a battery of (partly computerized) tests for intelligence, attention, working memory and interference control. Motivation and perceived academic competence were measured with self-, parent- and teacher questionnaires. Feedback processing and motivation for math was assessed with a standardized task and a newly developed math task which relates closely to actual math-performance feedback learning within primary school classrooms. Table 1.1 gives an overview of all dependent variables.