Anne Fleur Kortekaas-Rijlaarsdam

145 SUMMARY AND DISCUSSION 7 Furthermore, in our RCT we used medication doses identical to the clinical dose prescribed by the patients’ treating physician. Although this maximized ecological validity of our results, this may have resulted in doses of MPH that were suboptimal for academic performance. As titration was done in a classical manner (in contrast to double-blind titration, see MTA-group, 1999a), doses may also have been suboptimal for symptom improvement. However, parents- and teachers reported robust behavioral improvements with MPH compared to placebo. In addition to the disadvantage of classical titration, titration based on behavior may have resulted in doses that were not optimal for cognitive and academic performance (Hale et al., 2011). Clinical Implications and Future Directions As academic improvement is one of the main treatment goals (Wright et al., 2015) in ADHD, an important implication from this thesis is that we should tone down the expectations of parents, teacher and treating physicians about the short-term effects of MPH on academic performance: Parents, teachers and treating physicians should be advised about the limited and specific effects of this type of treatment on school performance. Further, the results from our meta-analysis and intervention study indicate that the potential of MPH to improve academic performance lies in those areas where children with ADHD underperform (i.e. math and reading). This may, however, not be specific to children with ADHD as cognitive enhancers generally affects skills or performance that are impaired or have room for improvement (Farah et al., 2004). Moreover, our results suggest that the potential for MPH to improve academic performance may differ between individuals (below-average performing children profited more from MPH than children who performed above-average). Further, as behavioral improvements partly mediated positive effects of MPH on math productivity, differences in behavioral treatment response may be predictive of the impact of MPH on academic performance. Thus, it is important to take individual differences in learning abilities and behavioral treatment response into account when prescribing stimulants to children. The results from this thesis further imply that future research should separately assess the effects of MPH on measures of accuracy and productivity and distinguish between academic subjects, preferably even between types of reading (word-reading versus reading comprehension) and types of math (automatization versus word problems) given the differential effects of MPH on these outcomes. Also, more research on the effects of MPH on spelling and reading (especially word reading) is necessary, as evidence is scarce and inconsistent. More research on the impact of moderators