Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, OH, and the University of Cincinnati College of Medicine, Cincinnati, OH.
OBJECTIVE: Although poor sleep is often reported in adolescents with attention-deficit/hyperactivity disorder (ADHD), prior studies have been correlational. This study investigated whether sleep duration is causally linked to sleepiness, inattention, and behavioral functioning in adolescents with ADHD.
METHOD: Seventy-two adolescents (ages 14-17 years) entered a three-week sleep protocol using an experimental crossover design. The protocol included a phase stabilization week, followed in randomized counterbalanced order by 1 week of sleep restriction (6.5 hours) and 1 week of sleep extension (9.5 hours). Sleep was monitored with actigraphy and daily sleep diaries, with laboratory visits at the end of each week. Analyses included 48 adolescents who had complete actigraphy data and successfully completed the sleep protocol (defined a priori as obtaining ≥1 hour actigraphy-measured sleep duration during extension compared to restriction). Parent and adolescent ratings of daytime sleepiness, ADHD symptoms, sluggish cognitive tempo (SCT), and oppositional behaviors were the primary measures. The A-X Continuous Performance Test (CPT) was a secondary measure.
RESULTS: Compared to the extended sleep week, parents reported more inattentive and oppositional symptoms during the restricted sleep week. Both parents and adolescents reported more SCT symptoms and greater daytime sleepiness during restriction compared to extension. Adolescents reported less hyperactivity-impulsivity during sleep restriction than extension. No effects were found for parent-reported hyperactivity-impulsivity, adolescent-reported ADHD inattention, or CPT performance.
CONCLUSION: This study provides the first evidence that sleep duration is a causal contributor to daytime behaviors in adolescents with ADHD. Sleep may be an important target for intervention in adolescents with ADHD.