Stressed Out! : Stress physiology in anxious children

Anxiety is a basic emotion, not typically pathologic but commonly adaptive when it facilitates anticipation to a threat or danger. However, when children perceive the world as full of threats and dangers, with no possibility to relax and to regard their living environment as safe, anxiety becomes pathologic. Variations in the activity of the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS), two major physiological stress systems, have been implicated as possible biological markers of pathological anxiety in children. Normally, activation of these stress systems leads to behavioral and physical adaptive changes that improve an organism’s ability to survive. In children with an anxiety disorder, the persistent stress they experience might lead to an excessive and prolonged stress system activation. In summary, this thesis focused on the role of stress physiology as a cause, correlate, and predictor of pediatric anxiety disorders with the ultimate goal to improve treatment and prognosis. The results of the studies described in this thesis suggest that stress physiology is a biological marker for the onset, severity, and course of anxiety problems in childhood. Altered physiological functioning of the stress systems, as a vulnerability factor, could influence the expression of clinical anxiety disorders. In addition, chronic and pathological anxiety problems, interfering with daily life and leading to a clinical anxiety disorder, have a different effect on physiological functioning than temporarily heightened, subclinical anxiety symptoms