Mindful attention as a mechanism underlying non-suicidal self-injury: evidence from a longitudinal intervention trial

Non-suicidal self-injury (NSSI) represents a significant public health issue, yet its underlying mechanisms are not fully understood. Theoretical models posit attentional deficits as key potential factors, but most supporting evidence has been cross-sectional. This study aimed to provide longitudinal evidence for the role of mindful attention, a mindfulness-related attentional process, in NSSI by leveraging data from a randomized controlled trial.

A total of 196 individuals with NSSI were randomized to 13 weeks of dialectical behavior therapy skills training (DBT-ST; n = 97) or social support group therapy (SSGT; n = 99). They completed baseline and post-treatment assessments of mindful attention (Mindful Attention Awareness Scale), NSSI frequency (Ottawa Self-Injury Inventory). Given its close link with mindful attention and NSSI, emotion dysregulation (Difficulties in Emotion Regulation Scale) was also assessed.

Results indicated that the DBT-ST group showed significantly greater improvements in NSSI behaviors, mindful attention, and emotion dysregulation compared to the SSGT group. Mediation analyses revealed that improvements in mindful attention did not directly mediate NSSI reduction. Instead, mindful attention contributed indirectly through improvements in emotion regulation, which in turn predicted reductions in NSSI frequency. Cross-lagged panel analyses further demonstrated that improvements in mindful attention prospectively associated with subsequent improvements in emotion regulation, underscoring mindful attention as an upstream process in the reduction of NSSI.

These findings indicated that attention deficits played a role in NSSI and suggested a potential sequential process in which DBT-ST-related improvements in attention may support subsequent gains in emotion regulation, which are associated with reductions in NSSI.