Living creatures are shaped by the their experiences in a constant process of adaptation. These experiences accumulate and so their relative weight diminishes across the lifespan. In children, the relative weight of new experience is high, and children's developing brains are programmed to learn like in no other life phase. Early adversities can thus have a major impact on later mental and physical health outcomes. However, the nature of impact of exposure to adversities early in life on further development is less straightforward than it may seem at first sight.

In this presentation, I will address and illustrate a couple of issues that manifest the complexity of this association.

The data will come from TRAILS (Tracking Adolescents’ Individual Lives Survey), a longitudinal study on the development of mental health from preadolescence into young adulthood, with bi- or triennial assessments from age 11 onwards, for a period of over fifteen years.

Results from various analyses indicate that early adversities do not lead to unfavorable outcomes in every person, and that the consequences of early adversities depend on their timing.

The experiences that individuals encounter during development are incorporated in a continuous process of adaptation that shapes them and keeps on doing throughout life. Considering the complexity and individuality of these processes, it is inevitable that research findings are often heterogeneous, and effect sizes small.

The author has not supplied his declaration of competing interest.