Results
self-injury, nonsuicidal self-injury
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.