Abstract Background The Open Dialogue approach (OD) emphasizes community-based psychiatric treatment for adolescents, but its success in achieving this is poorly documented.

Objective To analyse out-of-home intervention usage in a national sample of adolescent psychiatric patients and determine if OD is linked to increased time until out-of-home intervention.

Participants and setting The register-based cohort study included all adolescents aged 13–20 who received psychiatric treatment in Finland between 2003 and 2008. The research group (n = 780) included adolescents whose treatment was initiated in the Western Lapland catchment area, where OD covered the entire psychiatric service. The comparison group (n = 44,088) included the rest of Finland. National register data encompassed the period from treatment onset until the end of the 10-year follow-up or death. The primary outcomes of interest were the times to the first and second out-of-home intervention, including foster care, supportive housing, and hospitalization. The secondary outcomes included the clinical/demographic characteristics of adolescents treated out-of-home.

Methods The hypothesis was tested via an inverse probability of treatment–weighted Cox hazard model, plus within- and between-group comparisons to analyse the secondary outcome.

Results OD was associated with increased time to the first (adjusted hazard ratio [aHR]: 0.61, 95%CI: 0.52–0.72) and second (aHR: 0.75, 95%CI: 0.58–0.96) out-of-home interventions. In both service types, there was a subgroup of adolescents with repeated out-of-home interventions, who also demonstrated poorer long-term outcomes.

Conclusion OD-based psychiatric services for adolescents are associated with fewer out-of-home interventions. The clinical significance of the findings warrants further research.