A multi-method examination of sluggish cognitive tempo in relation to adolescent sleep, daytime sleepiness, and circadian preference.

Background: The field's understanding of the association between sluggish cognitive tempo (SCT) and sleep is severely limited by the lack of multi-method and multi-informant research designs that move beyond global ratings, often focused on a limited number of sleep-related domains, such as daytime sleepiness. The current study begins to address these limitations by using actigraphy, daily sleep diary, and self- and parent-report global ratings of sleep in adolescents, a developmental period marked by changes in SCT, sleep, and circadian function. As SCT and sleep are also associated with ADHD symptoms, we tested these associations in a sample of adolescents with and without ADHD.

Methods: Adolescents (N = 302; M age = 13.17 years, 44.7% female) with (n = 162) and without ADHD (n = 140) and parents completed global ratings of sleep and daytime sleepiness, and adolescents completed a measure of circadian preference. Adolescents also wore actigraphs for approximately two weeks, during which daily diaries were completed.

Results: Above and beyond demographic characteristics (i.e., sex, race, and family income), pubertal development, medication use, and ADHD group status, adolescents' self-reported SCT symptoms were uniquely associated with shorter sleep duration and later sleep onset per both actigraphy and daily diary. SCT symptoms were also uniquely associated with longer sleep onset latency and poorer overall sleep (per daily diary), more sleep/wake problems and daytime sleepiness (per adolescent rating), more difficulties initiating and maintaining sleep (per parent rating), and later eveningness preference (per adolescent rating). Nearly all significant effects remained in sensitivity analyses controlling for adolescent- or parent-reported ADHD symptom dimensions.

Conclusions: Findings provide the strongest evidence to date for SCT being uniquely linked to poorer sleep, greater daytime sleepiness, and a later evening circadian preference across subjective and objective measures. Longitudinal studies are needed to evaluate predictive and bidirectional associations.