title: Examining cortisol rhythmicity and responsivity to stress in children with Tourette syndrome.
abstract: BACKGROUND
  Tourette syndrome (TS) is characterized by motor and vocal tics, which are often exacerbated by stress. The hypothalamic-pituitary-adrenocortical (HPA) axis, a major stress response system is thus of interest for understanding TS.
  
  
  METHODS
  Diurnal cortisol rhythms were estimated in medication-free children 7-13 years with TS (N=20) and healthy age-matched controls (N=16). Salivary samples were collected on 3 consecutive days from the home. HPA responsivity was assessed by examining cortisol in response to a mock and real MRI scan.
  
  
  RESULTS
  The results of diurnal rhythmicity revealed a trend showing marginally lower evening cortisol for the TS group. By contrast, the TS group had higher cortisol levels in response to the stressor. There were strong, negative correlations between evening cortisol and tic severity as well as diurnal cortisol and anxiety.
  
  
  CONCLUSIONS
  The children with TS showed increased cortisol in response to the MRI environment, supporting a model of enhanced HPA responsivity. The lower evening cortisol may be the result of chronic daily stress. Alternatively, the negative associations between cortisol and reported anxiety and tics may reflect biologically based anxiolytic properties of tic expression. Taken together, the results clearly implicate involvement of the HPA axis in the neuropathology of TS.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of California at Davis, 2825 50th Street, Sacramento, CA 95817, USA. blythe.corbett@ucdmc.ucdavis.edu
authors.forename: B A
authors.initials: BA
authors.lastname: Corbett
authors.forename: S P
authors.initials: SP
authors.lastname: Mendoza
authors.forename: C L
authors.initials: CL
authors.lastname: Baym
authors.forename: S A
authors.initials: SA
authors.lastname: Bunge
authors.forename: S
authors.initials: S
authors.lastname: Levine
mesh_terms: D000293:Adolescent; D001007:Anxiety / Q000175:diagnosis / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000378:metabolism; D008297:Male; D012463:Saliva / Q000737:chemistry; D012720:Severity of Illness Index; D013315:Stress, Psychological / Q000378:metabolism*; D005879:Tourette Syndrome / Q000378:metabolism*
chemical_list: D006854:Hydrocortisone