A Nationwide Study of How a School Reform Differently Affected Adolescents’ Use of Mental Health Services

An adolescent’s school environment is thought to be important for development, yet their influence on use of mental health services remains unclear. Using a national school reform with stepwise implementation, we assessed schools’ contribution to service use. We linked population-wide administrative data - including personal, school and municipal identifiers - with health registry data from 2020 to 2023, covering ≥ 588,111 adolescents across ≥ 2965 Norwegian schools. Reform-by-school interactions were tested using multilevel models with random slopes for schools. On average, the reform reduced service use by 3% but also increased school-level variation: odds of service use increased in some schools and decreased in others. This variation remained significant after controlling for Covid-19 and municipality, increased over time and was stronger for girls. School type, size, and teaching assistant ratio explained 13% of the between-school variation. Future research should examine how individual characteristics interact with schools to shape service use.