Dialectical Behavior Therapy for Suicidal Self-Harming Youth: Emotion Regulation, Mechanisms, and Mediators.

OBJECTIVE:This study evaluated mechanisms, mediation, and secondary/exploratory outcomes in our randomized controlled trial evaluating dialectical behavior therapy (DBT) compared to individual and group supportive therapy (IGST). We expand on previously reported results indicating a DBT advantage at posttreatment on planned suicide/self-harm outcomes, and greater self-harm remission (absence of self-harm, post hoc exploratory outcome) during active-treatment and follow-up periods. METHOD:This was a multi-site randomized trial of 173 adolescents with prior suicide attempts, self-harm, and suicidal ideation. Randomization was to 6 months of DBT or IGST, with outcomes monitored through 12 months. Youth emotion regulation was the primary mechanistic outcome. RESULTS:Compared to IGST, greater improvements in youth emotion regulation were found in DBT through the treatment-period [t(498) = 2.36, p = .019] and 12-month study period (t(498) = 2.93, p = .004). Their parents reported using more DBT skills: posttreatment t(497) = 4.12, p < .001); 12-month follow-up t(497) = 3.71, p < .001). Mediation analyses predicted to self-harm remission during the 6- to 12-month follow-up, the prespecified outcome and only suicidality/self-harm variable with a significant DBT effect at follow-up (DBT 49.3%; IGST 29.7%, p = .013). Improvements in youth emotion regulation during treatment mediated the association between DBT and self-harm remission during follow-up (months 6-12, estimate 1.71, CI 1.01-2.87, p = .045). Youths in DBT reported lower substance misuse, externalizing behavior, and total problems at posttreatment/6 months, and externalizing behavior throughout follow-up/12 months. CONCLUSION:Results support the significance of emotion regulation as a treatment target for reducing self-harm, and indicate a DBT advantage on substance misuse, externalizing behavior, and self-harm-remission, with 49.3% of youths in DBT achieving self-harm remission during follow-up. CLINICAL TRIAL REGISTRATION INFORMATION:Collaborative Adolescent Research on Emotions and Suicide; https://www.clinicaltrials.gov/; NCT01528020.