title: A biological measure of stress levels in patients with functional movement disorders.
abstract: BACKGROUND
  While the presence of co-existing psychological stressors has historically been used as a supportive factor in the diagnosis of functional neurological disorders, many patients with functional neurological disorders deny the presence of these stressors. The stress response circuitry in these patients remains largely unexplored.
  
  
  METHODS
  We performed an observational study examining biological stress levels in patients with functional movement disorders as compared with matched healthy controls. Specifically, we compared levels of circulating cortisol, the end-product of the hypothalamic-pituitary-adrenal axis. Salivary cortisol samples were collected from patients with "clinically definite" functional movement disorders (n = 33) and their age- and sex-matched controls (n = 33). Collections were performed at five standardized time points, reflecting participants' diurnal cortisol cycles. To rule out confounders, participants also underwent extensive psychological assessment including Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Hamilton Anxiety Rating Scale, and Hamilton Rating Scale for Depression.
  
  
  RESULTS
  Patients with functional movement disorders did not differ from matched controls with respect to levels of circulating cortisol.
  
  
  CONCLUSIONS
  We demonstrate that current stress levels are not altered in patients with functional movement disorders. Our results warrant careful review of current management of patients with functional neurological symptoms, and suggest that the insistence on heightened stress levels in these patients is unjustified.
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA. Electronic address: carine.maurer@nih.gov.
authors.forename: Carine W
authors.initials: CW
authors.lastname: Maurer
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA; University of Louisville, Department of Neurology, Louisville, KY, USA. Electronic address: kathrin.lafaver@gmail.com.
authors.forename: Kathrin
authors.initials: K
authors.lastname: LaFaver
authors.affiliation: Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA. Electronic address: amelir@mail.nih.gov.
authors.forename: Rezvan
authors.initials: R
authors.lastname: Ameli
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA. Electronic address: ryan.toledo21@gmail.com.
authors.forename: Ryan
authors.initials: R
authors.lastname: Toledo
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA. Electronic address: hallettm@ninds.nih.gov.
authors.forename: Mark
authors.initials: M
authors.lastname: Hallett
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000150:complications*; D011569:Psychiatric Status Rating Scales; D012463:Saliva / Q000378:metabolism; D013223:Statistics as Topic; D013315:Stress, Psychological / Q000209:etiology* / Q000378:metabolism*
chemical_list: D006854:Hydrocortisone
keywords: Conversion disorder; Cortisol; Functional movement disorders; Hypothalamic-pituitary adrenal axis; Psychogenic movement disorders; Stress