Clinical implications of daytime sleepiness for the academic performance of middle school-aged adolescents with attention deficit hyperactivity disorder.

Sleep disturbances are significantly more common in youth with ADHD in comparison to youth without ADHD (Owens, 2009). Estimated prevalence rates for sleep disturbances in youth with ADHD range from 25 – 50% (Sung et al., 2008; Yoon et al., 2012). The most commonly cited sleep difficulties in youth with ADHD include problems with sleep latency, bedtime resistance, and daytime sleepiness (Chaing et al., 2010; Hvolby et al., 2009; Wiebe, et al., 2012). Importantly, significantly higher levels of sleep disturbance have been documented in youth with ADHD not taking psychotropic medications (Cohen-Zion & Ancoli-Israel, 2004; Stein, Weiss, & Hlavaty, 2012), suggesting that the high prevalence of sleep problems in this population is not simply an artifact of stimulant medication use. Although it is clear that youth with ADHD experience higher than expected rates of sleep disturbances, it is unknown whether these disturbances result in increased functional impairment. One domain where the clinical implications of sleep disturbances are particularly relevant is academic functioning. In non-ADHD samples, sleep disturbances are associated with worse cognitive performance, higher rates of internalizing and externalizing behavior problems (Astill et al., 2012), and impairment in academic functioning (Drake et al., 2003; Perez-Chada et al., 2007). Youth with ADHD exhibit considerable impairment with academic performance and achievement, including significantly lower school grades and achievement scores in comparison to their same-aged peers (Frazier et al., 2007). Interestingly, the mechanisms thought to underlie the academic impairments of youth with ADHD, namely inattention and deficits in executive function, are very similar to the deficits thought to lead to poor school performance in youth with sleep disturbances (Beebe, 2011). Specifically, both symptoms of inattention (Langberg et al., 2011) and deficits in executive function (Miller, Nevado-Montenegro, & Hinshaw, 2012) have been shown to predict the academic achievement of youth with ADHD. Despite these similarities, almost no research has been conducted examining whether sleep disturbances predict academic functioning in samples of youth with ADHD above and beyond symptoms of inattention. Mayes and colleagues (2008) evaluated the relative impact of ADHD symptoms, sleep, IQ, and neuropsychological functioning on academic achievement in a sample of 412 elementary-age children. In this study, children were not formally evaluated for ADHD however; parent ratings of ADHD symptoms were collected. Sleep was measured using scores generated from a full-night polysomnography (e.g. sleep latency, sleep efficiency, awakenings) and also with subscale scores from the parent-rated Pediatric Behavior Scale (PBS; e.g., difficulty falling asleep, daytime sleepiness, parasomnias). The authors reported that objective (i.e. polysomnography) and subjective (i.e. rating scale) measures of sleep were not significant in the final models predicting math and reading achievement. Intelligence, ADHD symptom ratings and neuropsychological task performance were associated with achievement, with IQ being the single best predictor (Mayes et al., 2008). In theMayes et al. (2008) study, academic functioning was defined as performance on a standardized achievement test, and the relationship between sleep and achievement was examined in an elementary school age sample. It has been argued that sleep problems are less likely to be detrimental to performance on standardized achievement tests because these tests are administered in one-to-one, controlled environments, where test administrators work to minimize the impact of inattention and to promote motivation (Beebe et al., 2010). Further, the middle childhood period is particularly important for the study of sleep disturbances given that adolescents have more autonomy over sleep behaviors and often have greater sleep restriction on school nights and report higher rates of daytime sleepiness (Beebe, 2011; Drake et al., 2003). Accordingly, it has been suggested that additional research is needed with adolescent samples, and that future research focus on the impact of sleep disturbances on school grades and parent- and teacher-rated academic performance, which are more likely to be impacted by daytime sleepiness (Beebe, 2011). Measurement of daytime sleepiness is considered particularly important because assessment of sleep problems (e.g. parasomnias and sleep-disordered breathing), and hours slept per night, does not fully account for problems with daytime sleepiness (Drake et al., 2003) and therefore, may not entirely capture associated problems with academic functioning (Carskadon et al., 1998; Owens et al., 2000). As such, the goal of this paper was to examine the relative contribution of hours slept per night and daytime sleepiness to the academic functioning of adolescents with ADHD. We hypothesized that sleep disturbances would have a detrimental impact on school grades and ratings of academic performance above and beyond symptoms of ADHD and relevant demographic variables.