A multicenter randomized controlled effectiveness trial of transdiagnostic treatment for adolescents with subthreshold anxiety and depressive symptoms
Child And Adolescent Mental Health
A multicenter randomized controlled effectiveness trial of transdiagnostic treatment for adolescents with subthreshold anxiety and depressive symptoms
Child And Adolescent Mental Health

A multicenter randomized controlled effectiveness trial of transdiagnostic treatment for adolescents with subthreshold anxiety and depressive symptoms

Psychol Med. 2026 Sep 4;56:e264. doi: 10.1017/S0033291726105443.

ABSTRACT

BACKGROUND: Depression and anxiety disorders and symptoms are among the leading causes of disability and global disease burden in young people. Scalable, unified interventions are required to address subthreshold emotional symptoms in adolescents as a preventive strategy. This study evaluated the effectiveness of a transdiagnostic treatment for adolescents with subthreshold emotional symptoms.

METHODS: A multicenter, two-arm, randomized controlled trial was conducted. The Unified Protocol for Adolescents (UP-A) was compared with an active control consisting of protocolized progressive relaxation. A total of 676 adolescents (72.6% female; Mage = 13.77; SD = 1.39; range = 12-18 years) participated in the study. Primary outcomes were self-reported depressive and anxiety symptoms at postintervention, 6 months, and 12 months. The trial is registered with ClinicalTrials.gov (NCT05322642).

RESULTS: Three hundred seventy-eight participants were allocated to the UP-A group and 298 to the control group. Adherence was high in both conditions (≈78% attended >70% of sessions). Both interventions showed significant reductions in depressive and anxiety symptoms over time, with no significant between-group differences. At 12 months, the UP-A group showed marginally lower depressive symptoms and neuroticism. Significant treatment effects favoring the UP-A were observed for hyperactivity, conduct problems, and total mental health difficulties. Improvements were maintained across most outcomes at both follow-ups.

CONCLUSIONS: The comparable improvements observed across both conditions suggest that structured, group-based school interventions may help reduce emotional symptoms in adolescents with subthreshold presentations, rather than reflecting the superiority of a specific protocol. These findings support their potential for broad dissemination within stepped-care frameworks and for enhancing accessibility and real-world effectiveness of evidence-based treatments.

PMID:42695201 | DOI:10.1017/S0033291726105443