Anne Fleur Kortekaas-Rijlaarsdam

39 MPH AND ACADEMIC PERFORMANCE: META-ANALYSIS 2 MPH (Storebø et al., 2015). In the meta-analysis by Storebø and colleagues, some evidence was found for a moderating effect of ADHD subtype and behavioral improvements, with highest MPH-efficacy for the inattentive subtype. Similarly, study characteristics also did not moderate efficacy of MPH on math performance, at least not for release system, trial duration, time of measurement, dosage and titration method. Thirteen studies used ER formulations, two studies reported on the effects of transdermal MPH and 19 studies reported on IR formulations. Results from our meta-regression suggest that ER formulations are equally effective as IR formulations in improving academic performance, which is in line with findings from individual studies comparing ER and IR formulations (Dopfner et al., 2004; Pelham Jr. et al., 1990; Swanson et al., 2004). We found no effects of titration method (clinical titration prior to the trial or fixed dosages) which is also in line with findings from (Storebø et al., 2015). Possibly, to optimize the effects of MPH on academic outcome, titration should be based on academic outcomes instead of on symptom improvements. The absence of an effect of dose on academic performance is in line with the findings from Prasad and colleagues (2013), who found no difference between studies comparing the effect of 0.3 mg/kg or 10 mg fixed dose to 0.6 mg/kg or 17.5-20 mg fixed dose on percentage seatwork completed. Also in line with this are the results from (Storebø et al., 2015), who found no effects of dose on symptom improvements. Strengths of the current review included a separate consideration of academic accuracy and productivity; including a distinction between academic subjects (math, reading and spelling); and the inclusion of randomized controlled trials only. There were, however, also some potential limitations. First, because we focused on effects with the optimal dose, we did not include dose-response analyses. Second, trial duration was generally short (between 1-7 days), limiting our conclusions to short-term effects of MPH on academic performance. Evidence for the longer-term benefits of MPH on academic performance is lacking thus far (Langberg & Becker, 2012). For obvious ethical and practical reasons evidence for such effects is unlikely to be generated from placebo-controlled trials – and is therefore outside the scope of the current review. It remains possible that short-term effects of MPH on both behavior and academic performance (i.e. productivity) summarized here, may translate into longer-term benefits. Furthermore, it should be investigated whether long terms benefits may be seen even where short term effects are not evident. On the basis of this review, we make a number of recommendations for future research. Some studies in the review relied on self-developed math or spelling test sheets. In the