Summary Substantial research attention has been devoted to understanding the importance and impact of sleep in children and adolescents. Traditionally, this has focused on mean sleep variables (e.g., a child’s “typical” or average sleep duration), yet research increasingly suggests that intraindividual variability (IIV) of sleep/wake patterns (sometimes referred to as sleep variability or night-to-night variability) regularly occurs and may have implications for adjustment. A systematic search of five electronic databases identified 52 empirical studies published between 2000 and 2015 that examined correlates of sleep IIV in children and adolescents, with a recent increase in the publication rate of such studies. Identified studies were often atheoretical and included post hoc analyses, though IIV in select aspects of sleep does appear to be associated with increasing age/pubertal status, non-White race, physical and neurodevelopmental conditions (e.g., attention-deficit/hyperactivity disorder; autism), psychopathology symptoms (e.g., anxiety, depression, inattention), body weight, stress, aspects of cognitive functioning, and poorer sleep functioning/habits. The limited intervention work examining sleep IIV in adolescents is promising, though studies are needed using more rigorous intervention designs. Clinical sleep recommendations may not only need to address overall sleep duration and sleep habits but also the stability of sleep duration and timing. It will be important for future research examining sleep IIV in children and adolescents to use a developmental framework in advancing theory pertaining to the causes, mechanisms, moderators, and outcomes of sleep IIV in youth, and a conceptual model is proposed to help guide such efforts.

CONTEXT: Mixed findings exist on whether stimulant medications alter youth sleep. OBJECTIVE:To determine the effect of stimulant medications on sleep.DATA STUDIES: Studies published through March 2015 were collected via CINAHL, PsycINFO, and PubMed. References of retrieved articles were reviewed.STUDY SELECTION: Eligibility criteria included studies with children/adolescents who had attention-deficit/hyperactivity disorder (ADHD), random assignment to stimulants, and objective sleep measurement. Studies that did not include information about key variables were excluded. DATA EXTRACTION: Study-level, child-level, and sleep data were extracted by 2 independent coders. Effect sizes were calculated by using random effects models. Potential moderators were examined by using mixed effect models.RESULTS: A total of 9 articles (N = 246) were included. For sleep latency, the adjusted effect size (0.54) was significant, indicating that stimulants produce longer sleep latencies. Frequency of dose per day was a significant moderator. For sleep efficiency, the adjusted effect size (20.32) was significant. Significant moderators included length of time on medication, number of nights of sleep assessed, polysomnography/actigraphy, and gender. Specifically, the effect of medication was less evident when youth were taking medication longer. For total sleep time, the effect size (20.59) was significant, such that stimulants led to shorter sleep duration. LIMITATIONS:Limitations include few studies, limited methodologic variability, and lack of unpublished studies.CONCLUSIONS: Stimulant medication led to longer sleep latency, worse sleep efficiency, and shorter sleep duration. Overall, youth had worse sleep on stimulant medications. It is recommended that pediatricians carefully monitor sleep problems and adjust treatment to promote optimal sleep.Department of Psychology, University of Nebraska-Lincoln, Lincoln, NebraskaMs Kidwell contributed to the conceptualization of the study, organized literature searches, coded the original studies, and drafted the introduction and discussion sections; Ms Van Dyk contributed to the conceptualization of the study, coded the original studies for reliability analyses, and reviewed and revised the manuscript; Ms Lundahl contributed to the conceptualization of the study, conducted the meta-analyses, and drafted the methods and results sections; Dr Nelson contributed to the conceptualization of the study and provided critical editing of the manuscript; and all authors approved the final manuscript as submitted.www.pediatrics.org/cgi

Poor sleep is related to increased obesity risk in adolescents, though the mechanisms of this relationship are unclear. This paper presents a conceptual framework of the various pathways that have been proposed to drive this relationship. In this framework, increased food reward, emotional reactivity, decreased inhibitory control, metabolic disturbances, poorer dietary quality, and disrupted meal timings may increase the likelihood of increasing overall energy intake. This paper further notes how poor sleep increases sedentary behavior and screen time, which likely limits overall energy expenditure. The model posits that these mechanisms result in an imbalance of energy intake and expenditure following poor sleep, intensifying the overall risk for obesity. Increases in food reward processes, decreases in insulin sensitivity, disrupted meal timing, and increases in sedentary behavior seem to be the most compelling mechanisms linking poor sleep with increased obesity risk in adolescents. Future directions and clinical implications of this framework are discussed.

This meta-analysis examined the effect experimental sleep restriction has on youth's attention and hyperactivity outcomes. Thirteen published studies containing 17 independent samples were included (N = 496). Random- and fixed-effects models were used to estimate pooled effect sizes and moderator effects, respectively. Results indicate that sleep-restricted youth had significantly worse attention outcomes than youth with extended sleep, but no differences were evident regarding hyperactivity. Significant moderators of this effect included age and sex. These results have important implications for both the prevention and treatment of attention problems, highlighting the need for health professionals to screen for and treat underlying sleep issues.