Sleep and the Developing Brain: What We Know, What We Don't, and Where to Act-A Systematic Review and Evidence and Gap Map.

Sleep supports cognition across the lifespan, but its significance may differ developmentally: in adults, it largely maintains and restores functioning within mature neural systems, whereas in children and adolescents it may also support the formation of cognitive, emotional, and self-regulatory capacities. This systematic review and evidence and gap map, prospectively registered in PROSPERO and conducted according to PRISMA 2020, searched PubMed, PsycINFO, Scopus, and Web of Science for studies of sleep duration, quality/fragmentation, timing/regularity, and daytime sleepiness in relation to executive function/self-regulation, attention/vigilance, emotion/behavior regulation, and academic functioning among typically developing children and adolescents. Twenty-five studies contributed 46 study-outcome links. Across nearly all populated evidence cells, more adequate sleep profiles were associated with better developmental outcomes. The strongest and most experimentally supported evidence concerned sleep duration in relation to executive function, emotion/behavior regulation, and academic functioning; evidence for sleep timing/regularity and daytime sleepiness was weaker and predominantly cross-sectional. Unlike adults, for whom sleep primarily restores a mature system, children may lose not only today's functioning but tomorrow's developmental trajectory when sleep is chronically curtailed. Sleep duration currently provides the strongest basis for intervention, whereas the long-term developmental effects of sleep quality, timing, regularity, and sleepiness require further longitudinal and experimental investigation during this formative period.