Effect of Internet-Delivered Emotion Regulation Individual Therapy for Adolescents With Nonsuicidal Self-Injury Disorder: A Randomized Clinical Trial

IMPORTANCE Nonsuicidal self-injury is prevalent in adolescence and associated with adverse clinical outcomes. Effective interventions that are brief, transportable, and scalable are lacking. OBJECTIVE To test the hypotheses that an internet-delivered emotion regulation individual therapy for adolescents delivered adjunctive to treatment as usual is superior to treatment as usual only in reducing nonsuicidal self-injury and that improvements in emotion regulation mediate these treatment effects. DESIGN, SETTING, AND PARTICIPANTS This 3-site, single-masked, randomized superiority trial enrolled participants from November 20, 2017, to April 9, 2020. Eligible participants were aged between 13 and 17 years and met diagnostic criteria for nonsuicidal self-injury disorder; they were enrolled as a mixed cohort of consecutive patients and volunteers. Parents participated in parallel to their children. The primary end pointwas at 1 month after treatment. Participantswere followed up at 3 months posttreatment. Data collection ended in January 2021. INTERVENTIONS Twelve weeks of therapist-guided, internet-delivered emotion regulation individual therapy delivered adjunctive to treatment as usual vs treatment as usual only. MAIN OUTCOMES AND MEASURES Primary outcome was the youth version of the Deliberate Selfharm Inventory, both self-reported by participants prior to treatment, once every week during treatment, and for 4 weeks posttreatment, and clinician-rated by masked assessors prior to treatment and at 1 and 3 months posttreatment. RESULTS A total of 166 adolescents (mean [SD] age, 15.0 [1.2] years; 154 [92.8%] female) were randomized to internet-delivered emotion regulation therapy plus treatment as usual (84 participants) or treatment as usual only (82 participants). The experimental intervention was superior to the control condition in reducing clinician-rated nonsuicidal self-injury (82% vs 47% reduction; incidence rate ratio, 0.34; 95% CI, 0.20-0.57) from pretreatment to 1-month posttreatment. These results were maintained at 3-month posttreatment. Improvements in emotion dysregulation mediated improvements in self-injury during treatment. CONCLUSIONS AND RELEVANCE In this randomized clinical trial, a 12-week, therapist-guided, internet-delivered emotion regulation therapy delivered adjunctive to treatment as usual was efficacious in reducing self-injury, and mediation analysis supported the theorized role of emotion regulation as the mechanism of change in this treatment. This treatment may increase availability of evidence-based psychological treatments for adolescents with nonsuicidal self-injury. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03353961