A project funded by the European Research Council (2015-2020)

Adolescent substance use, self-harm, suicides, and delinquency are large scale problems in most countries in Europe. Of gravest concern are suicides, which have increased by 60% worldwide during the last four decades and are now among the three leading causes of death in this age group (Wasserman et al., 2005; www.suicide.org). Often these problems arise when young people experience major stress and vulnerabilities in their lives and/or are the result of being born into adverse circumstances. Although, quite a lot is known about the effects of stress, there are still major gaps in our knowledge, especially in relation to how stress affects physiological and emotional reactions, and harmful behaviour, and whether those effects are preventable or reversible.

The LIFECOURSE research project focuses on the influence of stress on harmful behavioural outcomes among adolescents, including substance use, suicidal behaviour, self-inflicted harm, and delinquency.

The study uses a multilevel developmental framework to examine the influence of stress on these behavioural outcomes. Drawing on theories and well documented research on the effects of stress on physiological and emotional reactions, and harmful behaviour, the proposed framework brings together three different paradigms; biological, psychological and sociological. We elaborate on the bio-social link between stress and emotions and behaviour as well as mediating and moderating effects of multiple environmental factors experienced during specific developmental periods, and cumulatively over time, on behaviour during adolescence. The new knowledge that will be gained will be a more comprehensive understanding of how multiple factors, both social and biological, potentially from early on, intertwine in affecting harmful behaviour later on and whether – with support during adolescence – it is possible to buffer or reverse the negative effects of stress on behaviour among adolescents. The proposed research is critical to the understanding of these problems. It will stimulate more international research in this field and generate important scientific findings but more importantly, an understanding of these issues will lead to better policies, better planning and of course better quality of life for people who may have unfortunate start to their lives.

Specifically, we work on extending our previous cross-sectional studies of the correlates and trends of harmful behaviour among adolescents (e.g., Kristjansson, Sigfusdottir, Allegrante & Helgason., 2008, Kristjansson, James, Allegrante, Sigfusdottir, & Helgason, 2010; Sigfusdottir, Farkas, & Silver, 2004; Sigfusdottir, Kristjansson, Thorlindsson, & Allegrante, 2008; Sigfusdottir, Thorlindsson, Kristjansson, Roe, & Allegrante 2009; Sigfusdottir, Asgeirsdottir, Sigurdsson, & Gudjonsson, 2011) to a longitudinal study of the trajectories of risk factors, development, and behaviour from the prenatal period through adolescence. We will achieve this by using registry data, social surveys, and physiological measures of biological, psychosocial, and environmental factors operating at key developmental periods, and cumulatively throughout childhood. By doing this, we will have a unique opportunity for combining different traditions of stress research; first, by including data from a whole population of children, allowing us to test the effects of life conditions at the individual level, as well as within the larger social structure, such as schools and neighbourhoods; second, by including both environmental and biological data from a sample of children from the same cohort, making it possible to study the combined environmental and physiological effects; and third, by examining different mediators and outcomes, including physiological, emotional, and behavioural.