Abstract
Background and Objectives: Adolescence is a critical yet vulnerable developmental stage, characterized by increased exposure to stressful life events (SLEs), which are strongly linked to the onset and progression of depression. Although mindfulness has been consistently associated with lower depressive symptoms, the mechanisms underlying this relationship-particularly in adolescents-remain underexplored. Prior research suggests that mindfulness operates through cognitive mechanisms, such as reduced rumination, enhanced emotional regulation, and greater cognitive flexibility. However, much of this work is cross-sectional, limiting causal interpretation and often overlooking distinctions between direct and indirect effects. This study aimed to clarify two proposed pathways through which trait mindfulness may reduce depressive symptoms in adolescents: (1) a direct pathway involving core cognitive-emotional processes, and (2) an indirect pathway, where mindfulness supports more adaptive stress appraisal. A secondary objective was to assess whether these indirect effects vary across different types of stressful life events. Materials and Methods: We analyzed longitudinal data from 3897 adolescents (M_age = 15.9; 51.2% female) across four waves spaced approximately six months apart. Structural equation modeling (AMOS) was used to evaluate both direct and indirect effects of trait mindfulness on depression, with stress domains included in separate analyses. Results: Trait mindfulness was strongly negatively correlated with depression (r = -0.39 to -0.56). The direct effect of mindfulness on depression was substantial (β = -0.60 to -0.74), while indirect effects via cognitive reappraisal were smaller (β = -0.10 to -0.26 for stress reduction; up to -0.17 for depression). Indirect effects varied across stress domains and were generally modest. Conclusions: Mindfulness appears to reduce adolescent depressive symptoms through both direct and indirect pathways. The more pronounced direct effect likely reflects underlying mechanisms, such as reduced rumination and enhanced emotional regulation. Although weaker, the indirect pathway-mediated by more adaptive stress appraisal-adds meaningful explanatory value. Together, these findings underscore mindfulness as a key protective factor and highlight its potential for informing targeted, resilience-based interventions in adolescent mental health.