This study validates the measurement equivalence of the Problematic Short Video Use Scale (PSVU) through multi-group confirmatory factor analysis among high school ( n = 1277) and college students ( n = 733). The scale demonstrates form, weak, strong, and strict equivalence across educational stages and genders (ΔCFI≤0.01, ΔTLI≤0.05), establishing cross-group stability of a three-factor structure (behavioral change, physiological discomfort, social viscosity). College students scored significantly higher than high school students in total scores (d = 0.55) and across dimensions, particularly in behavioral change (d = 0.70) and physiological discomfort (d = 0.54). Females consistently scored higher than males across all dimensions (d = 0.32-0.52). Based on the theory of planned behavior and social compensation theory, these findings provide methodological support for identifying high-risk groups and developing differentiated intervention strategies for adolescent digital behavior.

This study, using a sample of 481 adolescents, aims to explore the relationship between ego-identity and problematic short video use in an online learning environment. The findings reveal that: (1) academic procrastination plays a significant mediating role in the relationship between ego-identity and problematic short video use; (2) both psychological resilience and academic procrastination function as a chain mediation between ego-identity and problematic short video use; and (3) there is a significant nonlinear relationship between psychological resilience and problematic short video use. This research provides a novel perspective for understanding the relationship between adolescents’ mental health and problematic behaviors. The results offer important insights for informing mental health education practices and designing effective intervention strategies.

Based on the theoretical framework of psychological barriers among third-party bystanders in school bullying contexts, grounded in Protection Motivation Theory and Ecological Systems Theory, this study developed and validated the “Adolescent Bystander Intervention Barrier Perception Scale” (ABIBPS). The initial item pool was developed through literature review and semi-structured interviews, followed by item analysis, exploratory and confirmatory factor analyses across three samples (middle school students, N = 388; middle school students, N = 474; upper elementary school students, N = 547). Results revealed a robust two-factor structure comprising “Personal Risk and Fear Perception” and “Intervention Efficacy and Outcome Uncertainty.” The scale demonstrated measurement invariance across different age groups, good internal consistency reliability, structural validity, and criterion-related validity. Correlation analyses indicated that adolescent bystander intervention barrier perceptions were significantly negatively associated with prosocial behavior, positive youth development, intentional self-regulation, and self-esteem. This study provides a valid measurement tool for understanding the psychological barrier mechanisms of bystander behavior in school bullying, offering significant theoretical and practical implications for promoting active intervention behaviors among adolescents.