title: Alterations in HPA-axis and autonomic nervous system functioning in childhood anxiety disorders point to a chronic stress hypothesis.
abstract: BACKGROUND
  It is of debate whether or not childhood anxiety disorders (AD) can be captured by one taxonomic construct. This study examined whether perceived arousal (PA), autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis measures can distinguish children with different primary diagnoses of clinical anxiety disorders (AD) from each other, and from a general population reference group (GP).
  
  
  METHODS
  The study sample consisted of 152 AD children (comparing separation anxiety disorder, generalized anxiety disorder, social phobia and specific phobia), aged 8- to 12-years, and 200 same-aged reference children. HPA-axis functioning was measured by a diurnal cortisol profile. ANS functioning was measured by continuous measures of skin conductance level in rest and during a mental arithmetic task and high frequency heart rate variability in rest. PA was assessed by a questionnaire.
  
  
  RESULTS
  The AD sample showed lower high frequency heart rate variability during rest, heightened anticipatory PA, higher basal and reactive skin conductance levels and lower basal HPA-axis functioning compared to the GP sample. The existence of three or more clinical disorders, i.e. a high clinical 'load', was associated with lower basal HPA-axis functioning, higher skin conductance level and lower posttest PA. Specific phobia could be discerned from social phobia and separation anxiety disorder on higher skin conductance level.
  
  
  CONCLUSIONS
  Our findings indicated that children with AD have specific psychophysiological characteristics, which resemble the psychophysiological characteristics of chronic stress. A high clinical 'load' is associated with an altered ANS and HPA-axis functioning. Overall, ANS and HPA-axis functioning relate to AD in general, accept for specific phobia.
authors.affiliation: Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Rotterdam, The Netherlands. Electronic address: g.dieleman@erasmusmc.nl.
authors.forename: Gwendolyn C
authors.initials: GC
authors.lastname: Dieleman
authors.affiliation: Department of Child Development, Faculty of Psychology and Education, Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: Anja C
authors.initials: AC
authors.lastname: Huizink
authors.affiliation: Department of Psychiatry, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Joke H M
authors.initials: JH
authors.lastname: Tulen
authors.affiliation: Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: Elisabeth M W J
authors.initials: EM
authors.lastname: Utens
authors.affiliation: Faculty of Social and Behavioral Science, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Hanneke E
authors.initials: HE
authors.lastname: Creemers
authors.affiliation: Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: van der Ende
authors.affiliation: Department of Child and Adolescent Psychiatry/Psychology, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
mesh_terms: D001008:Anxiety Disorders / Q000175:diagnosis* / Q000503:physiopathology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D008297:Male; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D012463:Saliva / Q000737:chemistry; D013315:Stress, Psychological / Q000503:physiopathology*; D011795:Surveys and Questionnaires
chemical_list: D006854:Hydrocortisone
keywords: Anxiety disorder; Autonomic nervous system; Child; Comorbidity, Severity; Cortisol; HPA-axis; Psychophysiology; Stress, Perceived arousal