Physiology in anxious children and adolescents: a systematic review and empirical thesis

Cognitive models of anxiety disorders, anxiety studies and diagnostic criteria highlight the role of physiology and somatic sensations in characterising and maintaining anxiety disorders. However, the bulk of research has focused on cognitive and behavioural components of anxiety disorders as targets for prevention and treatment programs, utilising adult samples. Studies indicate anxious adults demonstrate biased perception of somatic changes, and those individuals with anxiety exhibit abnormal physiological systems. It is unclear if these findings translate to children and adolescents with anxiety symptoms and disorders. We conducted a systematic review into the PsycINFO database, including the ancestry approach, and found 104 child and adolescent studies investigating physiology (hypothalamic-pituitary-adrenal axis and autonomic nervous system) at rest and/or reactivity to stress. The studies were largely heterogeneous, investigating healthy youths, youths with separation anxiety disorder, posttraumatic stress disorder, generalised anxiety disorder, social phobia, specific fears, high and low shy children, and high and low anxious children. Methodology varied greatly between studies; however, overall results indicate anxious youths demonstrate discordance or biased perception regarding their physical anxiety symptoms. There was some evidence that anxious youths have an elevated autonomic response to stress, and some evidence that they demonstrate a blunted physiological flexibility to stress, with less evidence that anxious youths have chronic hyperarousal. We discuss implications of the review's findings and future directions.