ADHD Treatment and Long-Term Academic Outcomes: Response to Arnold and Colleagues

Arnold, Hodgkins, Kahle, Madhoo, and Kewley (2020) conducted a systematic review of the literature to evaluate the impact of pharmacological, psychosocial, and multimodal treatment on the long-term academic outcomes of individuals with ADHD. This is an important topic given that a majority of youth with ADHD experience clinically significant academic impairment that persists into adolescence and emerging adulthood. Arnold et al. concluded that there is a large literature base documenting long-term (≥2 years) improvement in both academic achievement and performance following ADHD treatment, with greater evidence for improvement in achievement outcomes (e.g., standardized test scores) in comparison with performance outcomes (e.g., grades). The authors also concluded that improvements in academic functioning generally occurred irrespective of treatment modality (i.e., pharmacological, non-pharmacological, multimodal). These conclusions appear to be contrary to other recent reviews (e.g., Langberg & Becker, 2012; Parker, Wales, Chalhoub, & Harpin, 2013), which reported that few studies have evaluated the impact of treatment on long-term academic outcomes. The results of the Arnold et al. manuscript would also appear to be at odds with the conclusion from Langberg and Becker (2012) that pharmacological treatment is associated with statistically significant but educationally negligible long-term gains in academic achievement. Specifically, Arnold and colleagues conclude, “There is a large evidence-base demonstrating that ADHD treatment improves long-term academic outcomes, particularly achievement test outcomes” and suggest that one reason for the “difference in conclusions [across reviews] is likely due to the larger number of studies in the current analysis. ” In this response letter, we will evaluate the validity of these assertions. Assertion 1: In comparison with prior reviews, Arnold and colleagues identified more studies of long-term academic outcomes, which the authors suggest explains differences across reviews and perhaps lends greater credence to the Arnold et al. (2020) review. The abstract indicates that 176 studies conducted between 1980 and 2012 were included in the review. However, it is important to note here that the Arnold and colleagues review included multiple aims, with the first being to evaluate the impact of “untreated ADHD” on long-term academic outcomes. Thus, the first aim of the review did not focus on treatment effects but examined the degree to which individuals with ADHD experience poorer academic functioning than individuals without ADHD. The vast majority of studies included in the review aligned with this first aim, with far fewer studies actually examining long-term treatment effects on academics. When broken down into pharmacological, psychosocial, and multimodal treatment modalities (see Arnold et al., 2020; Figure 1), only eight pharmacological studies, eight psychosocial studies, and five multimodal studies were included in the authors’ review of long-term academic achievement outcomes. In terms of academic performance outcomes, there were only eight studies of pharmacological treatment, four of psychosocial, and three of multimodal. These figures are nearly identical to the number of studies included in prior reviews of long-term academic outcomes. For example, the Langberg and Becker (2012) review of pharmacological treatment included nine studies (eight distinct longitudinal samples); seven of which reported longterm academic achievement outcomes. Accordingly, differences between the Arnold et al. review and prior reviews are clearly not a function of the number of studies included and alternate explanations must be considered. Assertion 2: ADHD treatment results in significant longterm academic improvements. The Arnold et al. (2020) review concludes that 79% of achievement outcomes and 75% of performance outcomes were significantly worse when comparing youth with untreated ADHD with youth without ADHD. The authors also conclude that treatment was associated with significant improvement in academic achievement 79% of the time and academic performance 42% of the time. However, these conclusions must be considered in light of several important methodological issues. First, the Arnold and colleagues review dichotomized studies based on whether a statistically significant improvement was reported for a given outcome (i.e., yes/no), and effect sizes 577138 JADXXX10.1177/1087054715577138Journal of Attention DisordersLangberg and Becker research-article2015