Unraveling the temporal dynamics of psychological inflexibility and non-suicidal self-injury in adolescents: a three-wave random intercept cross-lagged panel analysis

This study explores the longitudinal relationship between psychological inflexibility and non-suicidal self-injury (NSSI) in adolescents, addressing a gap in the existing literature. A three-wave longitudinal design was adopted, with a random-intercept cross-lagged panel model (RI-CLPM) applied to differentiate between-person and within-person effects. The findings revealed a robust model fit (χ2(43) = 280.733, p < 0.001, CFI = 0.96, RMSEA = 0.04 (95%CI [0.04, 0.05])). At the between-person level, there was no significant association between psychological inflexibility and NSSI (β = 0.54, SE = 1.73, p = 0.75), whereas psychological inflexibility significantly predicted NSSI at the within-person level (β = 0.16, SE = 0.06, p = 0.01). Additionally, the study identified that external factors like location of residence and family economic status significantly influenced NSSI. These findings contribute to a deeper understanding of the role of psychological inflexibility in NSSI and highlight the importance of targeting this construct in therapeutic interventions for adolescents. Through a longitudinal approach, the study provides valuable insights into the dynamic mechanisms underlying NSSI behaviors, offering significant implications for clinical practice and future research.