Implementation and effectiveness of the web‑based skills training START NOW in adolescents in residential youth care: a cluster randomized controlled trial

BACKGROUND: Adolescents and young adults in residential youth care (RYC) face cumulated adversity and high emotional and behavioral problems yet face structural barriers that limit access to evidence-based mental health care. While digital tools promise scalability and flexibility, real-world implementation and effectiveness in vulnerable youth in institutional care remain understudied. OBJECTIVE: This study aimed to evaluate the implementation and effectiveness of a newly developed web-based self-help or group-facilitated version of the START NOW intervention in a three-arm cluster-randomized control trial for youth in RYC in Switzerland. METHODS: 164 adolescents and young adults (M = 16.6 years, SD = 1.5; 43.8% female) from 27 RYC institutions were enrolled in a 9-week self-help or group-facilitated START NOW intervention tested against treatment-as-usual (TAU). Psychological inflexibility was the primary outcome; secondary outcomes included trait resilience, well-being, self-efficacy, functional impairment, and distress. Surveys were administered at baseline, post-intervention, 3-, and 6-month follow-up. Primary analyses employed linear mixed models in an intention-to-treat approach imputing missing data to estimate treatment effects at 3-month follow up. The trial was registered: ClinicalTrials.gov Identifier: NCT05313581; 6th April 2022. RESULTS: The group-facilitated condition showed higher intervention compliance than the self-help help condition, over 50% of youth in the self-help group did not conduct a single session. Longitudinal follow‑up completion rates declined substantially, with only 37.8% providing data at T3 with the self-help group displaying the lowest levels (TAU 47.8%, 20.7% self-help, 48.3% facilitated group). No significant differences in psychological inflexibility or any secondary outcomes were found between study arms. CONCLUSIONS: In contrast to prior evidence from group-based START NOW interventions with more intensive facilitator support, the web-based START NOW adaptation evaluated in this found no evidence for additional benefits over TAU in RYC settings. Findings highlight critical implementation barriers to high attrition and missing data. Successful adoption of digital interventions in RYC require tailored, blended approaches with active facilitation and adaptive support structures.