Introduction
NSSI, Nonsuicidal self-injury, psychiatric, assessor-rated NSSI, impulsive self-destructive behaviors
SECONDARY
Nonsuicidal self-injury (NSSI), the deliberate destruction of one’s body tissue without suicidal intent,There are very few empirically supported treatments for NSSI in adolescence.One way to treat NSSI more effectively is to target key mechanisms underlying NSSI.This study presents the results from what is to our knowledge the first randomized clinical trial of internet-delivered treatment for adolescents with NSSID. The first aim was to investigate the efficacy of therapist-guided IERITA delivered adjunctive to treatment as usual (TAU) compared with TAU only. The second aim was to examine emotion regulation as a mechanism of change in IERITA. We expected that IERITA plus TAU, relative to TAU only, would lead to both larger reductions in self-reported and assessor-rated NSSI frequency and greater improvements in the secondary outcomes of emotion dysregulation, global functioning, impulsive self-destructive behaviors, and psychiatric symptoms. Finally, we expected that improvements in emotion regulation would mediate improvements in NSSI during treatment.