Bullying and victimization in schools: Causal relationship between adolescent disruptive behavior, sleep schedules, and extended school hours.

Very few studies have identified the relationship between chronotype, sleep habits, and bullying/victimization in school and online contexts. The objective of this work is to identify predictors of frequency of bullying/cyberbullying in Portuguese pubescent and adolescent populations, such as chronotype and sleep aspects, controlling for gender, age, grade, and school attendance hours. One hundred and seventeen Portuguese students from the second and third grades of elementary school were considered, 41 (34.5%) of which were males and 76 (63.9%) were females. The measures used were the Children's Chronotype Questionnaire and the Bullying and Cyberbullying Behaviors Questionnaire: Short Form (BCBQ‐SF). Percentile analyses, multivariate analysis of variance, nonparametric tests, and hierarchical and nonhierarchical linear logistic regression analyses were performed to confirm the prediction models and to identify causal variables moderating the effect of bullying and victimization in adolescents of various ages and school grades, with different school and sleep schedules. Adolescents with more episodes of victimization had higher sleeping problems, especially in terms of sleep duration (late hours of awakening/rest times and falling asleep, especially on days off); the school grade, the average daily school attendance hours, and school entrance time were some predictors found. The model differed in the variable of hours of curricular enrichment activities. The higher the eveningness score, the more aggression was reported. Practitioner points: Prediction models identified causal effect for bullying and victimization.Long school schedules were correlated to more bullying episodes. Curricular enrichment activities were significant predictors of lower bullying. [ABSTRACT FROM AUTHOR]