Early remission of deliberate self-harm predicts emotion regulation capacity in adulthood: 12.4 years follow-up of a randomized controlled trial of adolescents with repeated self-harm and borderline features.

Emotion regulation capacity, critical for adult functioning and mental health, develops strongly during adolescence in healthy individuals. Deficits in emotion regulation is often referred to as emotion dysregulation [ED] and is associated with various mental health problems, including repeated deliberate self-harm [DSH] which peaks in adolescence. Dialectical Behaviour Therapy for adolescents [DBT-A] systematically targets ED through strategies such as changing coping behaviours and has previously been shown to effectively induce DSH remission in adolescents. However, whether such remission is associated with improved emotion regulation capacity in adulthood, and whether this effect is mediated by changes in use of coping strategies has not been previously studied. Prospective long-term follow-up study of an RCT comparing DBT-A with enhanced usual care [EUC] for adolescents presenting to community child and adolescent psychiatric outpatient clinics with borderline personality features and repeated self-harm. Assessments included both structured interviews and self-report at baseline and 1.6, 3.1 and 12.4 years follow-up. In the final follow-up, adult ED was measured and data were collected for 61 (80%) of the original 77 participants. DSH remission was assessed at 1.6 years follow-up, and use of coping strategies at 3.1 and 12.4 years follow-ups. A mediation analysis was conducted within a causal inference framework. Both treatment groups increased their use of functional coping skills from adolescence to adulthood, while only DBT-A was associated with decreases in dysfunctional coping. There was a direct effect of DSH remission 1 year after treatment on adult ED, particularly for participants who did not receive DBT-A. There was a negative association between reductions in dysfunctional coping and adult ED, however this did not mediate the effect of DSH remission. This is the first study to report that early DSH remission in adolescence predicted lower ED in adulthood. These results highlight the importance of early DSH remission and provides new insight into the long-term relationship between DSH and ED. Clinical trial registration information: "Treatment for Adolescents with Deliberate Self-harm"; http://ClinicalTrials.gov/;NCT00675129.