Adolescence is characterized by a substantial rise in the prevalence of depressive disorder. While in adulthood lower socioeconomic position predicts a greater risk of depression, studies have found inconsistent evidence for social differentials in depression in adolescence and early adulthood. Numerous studies have documented that low childhood socioeconomic position predicts a higher risk of later depression, but less research has been conducted to investigate how the individual’s own educational track is associated with depression in adolescence and early adulthood. This thesis investigates whether the risk of depression varies by childhood socioeconomic position and personal educational track. Adopting the life-course perspective, this study examines how childhood socioeconomic position and own educational track combine to predict depression in late adolescence and early adulthood. A social pathway model anticipates that a low childhood socioeconomic position increases the risk of a low personal educational track which in turn increases the risk of later depression. Furthermore, the resource substitution model hypothesizes that the protective effect of a higher educational track is greater for those from more disadvantaged backgrounds substituting for the lacking childhood resources. Gender-specific determinants of depression are also examined. This thesis used annually updated individual-level register data EKSY014, which consisted of a 20-per-cent random sample of 0–14-year-olds living in private households in Finland at the end of year 2000. The study population of this study was restricted to individuals born in 1986–1990 (n=60,829), and they were followed over two educational transitory stages, firstly at age 17–19, and secondly at age 20–23 years. Depression was identified from health care registers maintained by The National Institute for Health and Welfare and The Social Insurance Institution of Finland. Survival analysis using Cox proportional hazards models was conducted to estimate the relative and combined effects of childhood socioeconomic position and educational track on the hazard of depression. According to the results, both low childhood socioeconomic position and lower personal educational track are associated with an increased risk of depression in late adolescence and early adulthood. School discontinuation and prolonged upper secondary schooling and also a vocational track among women predict a greater risk of depression compared to academic track. Educational track mediates the association between low childhood socioeconomic position and the risk of depression but is also independently associated with the risk. Early mental disorders also play a significant role in the process by influencing post-comprehensive tracking. The results further suggest that a higher educational track does not provide as effective protection against depression for 17–19-year-old adolescents if the individual lacks familial resources, but is more important for adolescents with higher socioeconomic backgrounds. Educational track does not moderate the effect of childhood socioeconomic position on depression among 20–23-year-olds. The results of this study fit in with the pathway conceptualization of the life-course approach. Educational track constitutes a social pathway mediating the effect of low childhood socioeconomic position on the risk of depression in adolescence and early adulthood. However, not all differences in risk by educational track are explained by childhood socioeconomic position but a lower educational track poses a risk on mental health independent of childhood resources. The findings do not support the resource substitution hypothesis among adolescents and young adults. In total, the findings demonstrate that early segregation of educational trajectories comes with differential chances for mental health.

Futures studies is a multidisciplinary field that integrates disciplinary information through discussion. This article integrates information from life-course research with futures studies. Life course research explores how human lives develop over time, focusing on the past and present. Futures studies may use this information to explore possible, probable, and preferable future developments of human lives. Life-course research defines a stable social context and standardized life-courses as a requirement for futures studies under shallow uncertainty. In this situation, important experiences in a person's life and social institutions create life-course patterns that may inform deterministic forecasts. Futures studies under medium uncertainty may be carried out when life-courses change gradually over time or when similar countries are compared. Here, personality also creates life-course patterns that may inform probabilistic forecasts. When social contexts change fundamentally or unexpectedly, then futures studies under deep uncertainty are called for. In this situation, important events, social institutions, and personality may inform foresight on future life-course patterns. Finally, futures studies under recognized ignorance may use previous life-course research for inspiration. These insights contribute to cumulative knowledge building, and they underline the opportunities and limitations of futures studies.