By Nestor Lopez-Duran PhD
A few weeks ago I discussed a research study that examined the effects of the medication Concerta (methylphenidate) on performance variability during cognitive tasks in children with ADHD. But does this translate to improvements in school work? Does the research support the effectiveness of ADHD meds in more tangible outcomes, such as grades or academic achievement?
Surprisingly, there is a lack of longitudinal long term research exploring the effectiveness of ADHD medication across multiple grades. Instead, most ADHD research examining academic outcomes are relatively short (within one year) or have very small sample sizes. However, in the latest issue of the Journal of the American Academy of Pediatrics, Dr. Richard Scheffler and a team from the University of California at Berkeley, reported the findings of a comprehensive long term examination of the effectiveness of ADHD medications on academic achievement.
The authors examined a representative population cohort of children entering Kindergarten in the late 1990s. The study cohort included 11,890 children who entered Kindergarten in 1998. These children were examined yearly until the end of their 5th grade. The authors gathered information on whether the child had an ADHD diagnosis, whether the child was taking medication (more of this below), and the mathematics and reading achievement levels of all the kids during the 5 year study.
The estimation of the medication use was a bit tricky. During 5th grade, the families were asked whether the child was taking medication for ADHD at that time. If the child was not taking medication, the authors assumed that the child had not taken ADHD medication during the duration of the study. If the child was taking a medication in 5th grade, the parents were then asked to report the length of medication use, which was used to estimate past years use.
The authors then compared children who had been medicated to those with a diagnosis of ADHD but who had not received any medications.
- 9% of the sample had a life-time diagnosis of ADHD by 5th grade. This does not mean that 9% of 5th graders had ADHD. It means that by 5th grade, 9% of those who entered kindergarten in 1998 had received an ADHD diagnosis sometime during their lives.
- 68 % of kids with ADHD had taken medication for their condition.
- While controlling for a number of individual and family characteristics, medicated ADHD kids had significantly higher mathematics achievement scores across the different grades than the non-medicated ADHD kids. Although this difference is statistically significant, the authors reported that the gains represent the average gain expected during 0.19 school year over a 6 year period.
- There was no difference between those medicated at a single year vs. those medicated at multiple years in their mathematics achievement scores.
- Children who were medicated in multiple years had significantly higher reading achievement scores than the non-medicated ADHD peers. This reflects gains of 0.29 school years over 6 years.
Despite the limitations of this study regarding how medication use was estimated (retrospectively via parental report, no information on dosage, gaps in administration, etc), there is one very compelling overall finding: If we are to assume that severity of ADHD is associated with the likelihood of medication use (the more severe the more likely you are to be medicated), these findings show that medications are effective in improving academic achievement even among these severe kids. But we cant test that hypothesis because the study did not include data about the initial severity of ADHD prior to medication use. Someone could also argue that the effects observed were not due to the medication, but instead to other untapped family characteristic that differentiated those who tried medications vs. those who did not. That is, it is possible that factors that make a family more likely to try medication for their ADHD kids contribute to the kids better long-term academic performance.
The reference: Scheffler, R., Brown, T., Fulton, B., Hinshaw, S., Levine, P., & Stone, S. (2009). Positive Association Between Attention-Deficit/ Hyperactivity Disorder Medication Use and Academic Achievement During Elementary School PEDIATRICS, 123 (5), 1273-1279 DOI: 10.1542/peds.2008-1597