Predicting health: The role of the early life environment

The mechanism underpinning the developmental origins of health and disease (DOHaD) hypothesis can be seen as perinatal programming, whereby environmental factors predispose to later health outcomes via a shift in the functional 'tone' of physiological systems. Thus, the developing organism 'senses' the early life environment and uses this information to systematically establish homeostatic set points. This chapter focuses on the role that the perinatal environment plays on later psychological outcomes. Although psychological stress experienced in early life is clearly a substantial contributor to the development of later-life psychopathologies, another important factor, and the focus of the chapter, is exposure to immunological stressors. The chapter outlines the major pathways through which peripheral immune activation signals the brain. The hypothalamic-pituitary-adrenal (HPA) axis is particularly vulnerable to environmental influences during the neonatal period. Early-life developmental plasticity allows an organism to shape its unique phenotypic characteristics in response to given environmental conditions.