Inequalities in adolescent mental health and allocation of students to selective classes in comprehensive schools in Finland: a longitudinal study.

Background: Lower socioeconomic positions (SEP) and poor academic achievement increase children's risk for mental health problems. The Finnish education system is officially non-selective and unified, but a part of children can be selected into emphasised teaching classes by aptitude tests, which are known to segregate students by SEP and academic achievement. We study here if allocation of students to mainstream and selective classes segregates students by mental health, too.