The present study investigated the longitudinal and reciprocal associations between psychological distress and psychological inflexibility among college students. A total of 391 participants (77.2% male; age = 20.31, SD = 0.90) were recruited through cluster sampling, completed the DASS-21 (21-item Depression Anxiety Stress Scale) and AAQ-II (Acceptance and Action Questionnaire–II) at two time points (T1: March 2024; T2: October 2024). After establishing longitudinal measurement invariance, a cross-lagged panel model was estimated while controlling for gender and age. Results from cross-lagged panel modeling (CLPM) revealed significant concurrent correlations between psychological distress and psychological inflexibility at both time points, as well as reciprocal predictive effects: T1 psychological distress significantly predicted higher T2 psychological inflexibility (β = 0.155, p = 0.006), and T1 psychological inflexibility significantly predicted higher T2 psychological distress (β = 0.186, p < 0.001). Gender was also significantly associated with baseline distress. These findings highlight the developmental interplay between psychological distress and psychological inflexibility consistent with the core assumptions of Acceptance and Commitment Therapy (ACT). These findings provide empirical support for prevention and intervention strategies grounded in ACT-based approaches, such as acceptance, mindfulness, and values-oriented action, to promote mental health in young adulthood.
Li et al. (2026) studied this question.