Stress-system activation in children with chronic pain: A focus for clinical intervention

Abstract

Accumulating evidence indicates that psychological and neurophysiological processes interconnect and interact to activate the body's stress system and to trigger and maintain functional somatic symptoms. This study used the Early Life Stress Questionnaire, Depression Anxiety Stress Scales and biological markers (heart rate, heart rate variability, skin conductance, C-reactive protein (CRP) titre, respiratory rate, and accuracy and reaction time in an emotion-face identification task), to examine childhood adversity, psychological distress and stress-system activation in 35 children and adolescents (23 girls and 12 boys, 9-17 years old) disabled by chronic pain (vs two groups of age- and sex-matched healthy controls). Patients reported more early-life stress (U = 798.5, p = .026) and more psychological distress (U = 978, p < .001). They showed activation of the autonomic system: elevated heart rate (U = 862.5, p = .003), elevated electrodermal activity (U = 804.5, p = .024) and lower heart rate variability in the time domain (U = 380.5, p = .007) and frequency domain (U = 409.5, p = .017). The group showed an upward shift of CRP titres (with 75th and 90th CRP percentiles of 4.5 and 10.5 mg/L, respectively), suggesting the activation of the immune-inflammatory system. Elevated CRP titres were associated with elevated heart rate (p = .028). There were no differences in respiratory rate or in accuracy and reaction time in the emotion-face identification task. The results indicate that interventions for children and adolescents with chronic pain need a multidisciplinary mind-body approach that concurrently addresses psychological distress, physical impairment and stress-system dysregulation.

Keywords: Chronic pain; disorders of adaptation; functional somatic symptoms; stress system.