The purpose of the study is to evaluate the efficiency of dialectical behavior therapy (DBT) in treatment of adolescents with deliberate self harm compared to Enhanced Usual Care (EUC). Eighty patients in the age of 12-18 yrs old will be included in the study. The main inclusion criterion is repetitive deliberate self-harm. The patients will receive 16 weeks treatment in outpatient clinics in Oslo, after having been randomized to DBT or EUC. They will be assessed on five different time-points: baseline (before starting treatment), 6 weeks (after start of treatment), 12 weeks, 16 weeks and 68 weeks.