Brief digital psychological intervention to prevent relapse of non‐suicidal self‐injury behavior in adolescents: A randomized controlled trial

Background Non‐suicidal self‐injury (NSSI) poses a significant mental health challenge among adolescents, necessitating accessible and effective interventions. While the development of technology offers new opportunities, higher costs remain a concern. In this context, digital psychological interventions such as text message intervention (SMS) present a convenient and low‐cost delivery method that requires no face‐to‐face contact. However, the extent to which this method could function as a viable strategy remains underexplored. Objective To evaluate the effectiveness of an SMS intervention specifically developed for NSSI among adolescents when combined with treatment as usual (TAU), compared to TAU alone. Methods A randomized controlled trial (RCT) was conducted with 86 Chinese adolescents, randomly assigned to either the SMS intervention plus TAU or TAU alone. The SMS intervention, consisting of text messages addressing NSSI‐related knowledge, distress tolerance skills, and emotion regulation strategies, was administered over 8 weeks. Assessments were conducted at baseline, 4 weeks, and 8 weeks. Results Participants in the intervention group showed a significant reduction in NSSI behavior at 4 weeks (RR = 0.43, p < .001), though this effect was not significant at 8 weeks (RR = 0.84, p = .265). No significant changes in NSSI ideation were observed at 4 weeks (RR = 0.87, p = .221) or 8 weeks (RR = 1.10, p = .437). Resistance to NSSI urges increased significantly at 8 weeks in the intervention group (RR = 1.93, p = .002), but not at 4 weeks (RR = 1.44, p = .063). Secondary outcomes showed no significant changes. Conclusions The low cost, scalability, and accessibility of SMS interventions make them a potentially valuable complementary tool for supporting self‐harm populations. However, further research is necessary to confirm their efficacy across diverse settings and to determine how best to integrate them with comprehensive treatment strategies.