Uppsala Longitudinal Adolescent Depression Study (ULADS).

Purpose To present the Uppsala Longitudinal Adolescent Depression Study, initiated in Uppsala, Sweden, in the early 1990s. The initial aim of this epidemiological investigation was to study the prevalence, characteristics and correlates of adolescent depression, and has subsequently expanded to include a broad range of social, economic and health-related long-term outcomes and cost-of-illness analyses. Participants The source population was first-year students (aged 16-17) in upper-secondary schools in Uppsala during 1991-1992, of which 2300 (93%) were screened for depression. Adolescents with positive screening and sex/age-matched peers were invited to a comprehensive assessment. A total of 631 adolescents (78% females) completed this assessment, and 409 subsequently completed a 15year follow-up assessment. At both occasions, extensive information was collected on mental disorders, personality and psychosocial situation. Detailed social, economic and health-related data from 1993 onwards have recently been obtained from the Swedish national registries for 576 of the original participants and an age-matched reference population (N=200 000). Findings to date The adolescent lifetime prevalence of a major depressive episode was estimated to be 11.4%. Recurrence in young adulthood was reported by the majority, with a particularly poor prognosis for those with a persistent depressive disorder or multiple somatic symptoms. Adolescent depression was also associated with an increased risk of other adversities in adulthood, including additional mental health conditions, low educational attainment and problems related to intimate relationships. Future plans Longitudinal studies of adolescent depression are rare and must be responsibly managed and utilised. We therefore intend to follow the cohort continuously by means of registries. Currently, the participants are approaching mid-adulthood. At this stage, we are focusing on the overall long-term burden of adolescent depression. For this purpose, the research group has incorporated expertise in health economics. We would also welcome extended collaboration with researchers managing similar datasets.