Introduction: According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the self-injury syndrome is defined as a disorder on which more studies should be conducted. Given the prevalence and consequences of the non-suicidal self-injury disorder (NSSID) among adolescents and the introduction of a new class of NSSID in DSM-5, certain interventions are required for dealing with such behaviors among adolescents with NSSID. Emotion regulation group therapy (ERGT( is a novel treatment specific to Deliberate Self-Harm. The aim of this study was to analyze the effectiveness of emotion regulation therapy among adolescents with NSSID. Case Presentations: The case was a 15-year-old female student of the ninth grade diagnosed with NSSID. She received 14 sessions of emotion regulation therapy weekly. She filled out the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS), the Deliberate Self-Harm Inventory, Difficulty in Emotion Regulation Scale (DERS), the Beck Depression Inventory (BDI-II), and the Beck Anxiety Inventory (BAI) at baseline in addition to undergoing the intervention and follow-up. Conclusion: According to the research findings, the proposed treatment method decreased the participant’s scores on BDI-II, BAI, and DERS. It also reduced the frequency of self-injury behaviors. These effects lasted in the follow-up, too. The research findings indicated that emotion regulation therapy had a positive effect on adolescents with NSSID.
