From cortical and white matter structure to meaning: a brain-constrained neural network of semantic grounding in action and perception.

Adolescence is a critical developmental period characterized by profound physical, cognitive, and psychosocial changes, making it a highly vulnerable time for the onset of mental health disorders (). In recent years, psychological issues such as depression, anxiety, and academic stress have become increasingly prevalent among middle and high school students, raising significant public health concerns (). Closely intertwined with daytime psychological functioning is sleep quality. Adequate sleep is fundamental to adolescent neurodevelopment and emotional regulation; conversely, poor sleep quality, delayed bedtimes, and insufficient sleep duration are well-documented risk factors associated with emotional instability and psychological distress (). Understanding the complex relationship between sleep patterns and mental health is essential for developing effective early intervention strategies for this demographic. The outbreak of the COVID-19 pandemic introduced unprecedented disruptions to the daily lives and educational routines of adolescents globally (). To mitigate the spread of the virus, traditional in-school learning was frequently replaced by prolonged periods of home-based online learning. While necessary from a public health perspective, this drastic shift isolated students from their peers, altered their daily structures, and often increased prolonged screen time, all of which have been linked to deteriorating sleep quality and heightened psychological burden (). Furthermore, the transition back and forth between home-based learning and the highly structured, academically demanding environment of in-school learning presented its own unique set of stressors. Evaluating how these different learning modalities specifically impact the psychological well-being and sleep hygiene of students remains a critical area of ongoing research (). A two-country study reported immediate psychological effects of COVID-19 quarantine on youth from Italy and Spain, two of the most affected countries, highlighting the global impact of school closures on adolescent mental health (). A systematic review found that COVID-19 has significantly affected children and youth mental health internationally, emphasizing the need for targeted interventions (). Additionally, research on sleep and mental health in children and adolescents during the pandemic from multiple countries demonstrated disrupted sleep patterns and associated psychological challenges, underscoring the relevance of learning modalities for sleep hygiene (). While the pandemic's psychological impact on adolescents has been widely studied, few investigations have directly compared home-based online learning with in-school learning regarding psychopathological symptoms and sleep patterns. This study aims to: (1) compare mental health (assessed by MMHI-60 and PHQ-9) and sleep quality between adolescents engaged in home-based online learning vs. in-school learning; (2) examine the independent association between subjective sleep quality and mental health outcomes; and (3) explore whether these associations differ by learning modality, gender, or educational stage. Rather than solely reporting prevalence, we evaluate these relationships using multivariable regression, providing evidence to inform school-based mental health interventions and educational policy during public health emergencies.