The role of psychosocial stress in childhood for structural and functional brain development:neurobiological basis of developmental psychopathology

This review summarizes some important principles of human brain development. Special emphasis is placed on the role of psychosocial stress during childhood on the developing brain. Depending on the degree of cognitive, behavioral and socio-emotional maturation, previous experiences and actual context, psychosocial stressors may be perceived by children as being either controllable (challenge) or uncontrollable (disaster). Controllable stress experiences are associated with a preferential activation of the central and peripheral noradrenergic system, i.e., of a system endowed with the gating of cortical information processing and the facilitation and stabilization of neuronal pathways and synaptic connections involved in behavioral responding. Uncontrollable stress responses are elicited if all previously acquired behavioral or cognitive strategies are inadequate or fail to overcome the stressor. The resulting severe and long-lasting activation of the central stress responsive systems will finally lead to a full activation of the HPA system, accompanied by adrenocortical cortisol release. The major central effect of this response is the destabilization of previously established neuronal circuits and synaptic connections. Thus, severe uncontrollable psychosocial stress may act as an important trigger of and a prerequisite for the reorganization of neuronal connectivity. It may, above a certain threshold, threaten the mental and affective stability, integrity, and the future development of a child. The long-term consequences of psychosocial stress on the structural and functional maturation of the brain are documented by findings from animal research and by results in the field of developmental psychopathology in children. The role of risk and protective factors during different phases of child development is briefly summarized and the need for a biopsychosocial model concerning the relationship between human brain development and behavior is emphasized.