Considering Substance Use in Dysfunctional Beliefs About Sleep: Validation of the DBAS-S.

Adolescence is a critical period for personality development, self-regulation, and social maturation [, ]. During this stage, self-concept is still developing [], and heightened social sensitivity renders adolescents’ mental health particularly vulnerable to negative social experiences. Among the consequences of psychological distress during this period, depression is a prevalent internalizing disorder that not only impairs emotional functioning and social adjustment [] but also constitutes a significant public health burden. According to the Global Burden of Disease (GBD) Study [], depression has become one of the three leading causes of disability among adolescents. Extensive empirical research across diverse cultural contexts has identified school bullying victimization as a key risk factor for adolescent depression [–]. Compared with their non-bullied peers, victims of bullying are more likely to experience low self-esteem, loneliness, and emotional disorders, and they are at increased risk for substance abuse and eating disorders [, ]. This association is further supported by meta-analytic evidence demonstrating that bullying victimization is a significant risk factor for depression in children and adolescents []. However, bullying victimization is not a unidimensional construct but rather a multifaceted phenomenon encompassing physical, verbal, relational, and cyberbullying forms []. Research has shown that each of these four distinct types of victimization is positively associated with adolescent depression [, ]. At the same time, these forms differ in their directness, visibility, social meaning, and the extent to which victims can avoid them. Physical victimization involves direct bodily harm or threat, verbal victimization undermines self-worth through insults or humiliation, relational victimization disrupts social belonging through exclusion or manipulation, and cyberbullying victimization extends harm across time and contexts due to its persistent and often inescapable nature [, –]. These distinctions suggest that, although all forms are harmful, their pathways to depressive symptoms may not be identical [–]. Therefore, conceptualizing bullying victimization as a multidimensional phenomenon may provide a more nuanced understanding of how different peer stressors contribute to adolescent depression. To provide a unifying theoretical framework explaining why these distinct forms of victimization may each contribute to depressive symptoms, the present study draws on Self-Determination Theory (SDT) []. SDT posits that human well-being depends on the satisfaction of three basic psychological needs, competence, relatedness, and autonomy, and that persistent frustration of these needs increases vulnerability to psychological distress, including depression [, ]. From this perspective, different forms of bullying victimization may represent distinct pathways to a common adverse emotional outcome. Physical victimization may undermine safety and autonomy; verbal victimization may erode competence and self-worth; relational victimization may frustrate belonging and relatedness; and cyberbullying victimization may simultaneously threaten competence, relatedness, and perceived control over one’s social identity [–]. Although these forms differ in expression, they may converge in their tendency to frustrate basic psychological needs, thereby increasing depressive symptoms over time. Existing longitudinal evidence is broadly consistent with this perspective, indicating that physical, verbal, relational, and cyberbullying victimization are each associated with subsequent depressive symptoms among adolescents [, ]. Based on this framework and prior empirical findings, we propose Hypothesis 1: each of the four forms of bullying victimization at T1 will be positively associated with depressive symptoms at T2.