Anne Fleur Kortekaas-Rijlaarsdam

27 MPH AND ACADEMIC PERFORMANCE: META-ANALYSIS 2 I N T RODUC T I ON The neuro-developmental disorder Attention-Deficit Hyperactivity Disorder (ADHD), is characterized by inattention, hyperactivity and impulsivity (American Psychiatric Association, 2013). These symptoms are associated with academic problems such as lower grades, grade repetition and increased school drop-out (Barry, Lyman, & Klinger, 2002; G. J. DuPaul, 2007; Frazier et al., 2007; Polderman et al., 2010). Academic improvement is a common treatment target for children with ADHD with stimulant medication being the most commonly prescribed treatment (Wright et al., 2015). Stimulants are clinically effective in reducing ADHD symptoms in the short- and medium-term (MTA-group, 1999a; Van der Oord et al., 2008). Moreover, there is evidence that its’ benefits extend to improvements in cognition relevant for academic performance (Coghill, Seth, et al., 2014). In the past, there have been several reviews of the effects of stimulant medication on academic performance (Aman, 1980; Arnold et al., 2015; Barkley, 1977; Barkley et al., 1978; Langberg & Becker, 2012; Prasad et al., 2013; Schachar & Tannock, 1993). These reviews report little evidence for positive effects (Aman, 1980; Barkley, 1977; Barkley et al., 1978; Schachar & Tannock, 1993). However, the first meta-analysis (Prasad et al., 2013), demonstrated 9.7-14.4% (p<.001) improvements with stimulant medication compared to placebo in seatwork productivity (number of assignments completed) and on-task behavior (amount of time actively spend on seatwork). However, the effect of stimulant medication on the quality of academic performance (academic accuracy) was less clear-cut: In one analysis, only a third of the studies reviewed reported effects of medication on academic accuracy and the pooled effect was not significant (Prasad et al., 2013). The existing reviews (Aman, 1980; Arnold et al., 2015; Barkley, 1977; Barkley et al., 1978; Langberg & Becker, 2012; Prasad et al., 2013; Schachar, & Tannock, 1993) and meta-analysis by Prasad et al. (2013) have a number of limitations. Firstly, because the negative association between ADHD-symptoms and both reading and math is stronger than the association between ADHD-symptoms and spelling (Frazier et al., 2007) and there is evidence from recent medication trials that medication efficacy differs between academic subjects (Kortekaas-Rijlaarsdam, Luman, Sonuga-Barke, Bet, & Oosterlaan, 2017b; Murray et al., 2011), it is important to independently assess the effects of medication on different academic subjects. The meta-analytic results of Prasad and colleagues (2013) only applied to seatwork assigned by participant’s teachers (independent of the academic subject) and therefore tell us little about the possible