title: Panic and comorbid depression and their associations with stress reactivity, interoceptive awareness and interoceptive accuracy of various bioparameters.
abstract: BACKGROUND
  While current theories on perception of interoceptive signals suggest impaired interoceptive processing in psychiatric disorders such as panic disorder or depression, heart-rate (HR) interoceptive accuracy (IAc) of panic patients under resting conditions is superior to that of healthy controls. Thus, in this study, we chose to assess further physiological parameters and comorbid depression in order to get information on how these potentially conflicting findings are linked together.
  
  
  METHODS
  We used a quasi-experimental laboratory design which included multi-parametric physiological data collection of 40 panic subjects and 53 matched no-panic controls, as well as experimental induction of stress and relaxation over a time-course.
  
  
  METHODS
  Stress reactivity, interoceptive awareness (IAw; from the Body Perception Questionnaire (BPQ)) and IAc (as correlation between self-estimation and physiological data) were major outcome variables. Self-estimation of bioparametrical change was measured via numeric rating scales.
  
  
  RESULTS
  Panic subjects had stronger HR-reaction and more accurate HR-interoception. Concurrently, though, their IAc of skin conductance level, pulse amplitude and breathing amplitude was significantly lower than that of the control group. Interestingly, comorbid depression was found to be associated with increased IAw but attenuated IAc.
  
  
  CONCLUSIONS
  Demand characteristics and a categorical approach to panic confine the results.
  
  
  CONCLUSIONS
  The potentially conflicting findings coalesce, as panic was associated with an increase of the ability to perceive the fear-related parameter and a simultaneous decrease of the ability to perceive other parameters. The superordinate integration of afferent signals might be impaired.
authors.affiliation: Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany. Electronic address: jan.limmer@uk-erlangen.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Limmer
authors.affiliation: Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kornhuber
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany; Clinical Psychology and Psychotherapy, University of Wuppertal, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Martin
mesh_terms: D000328:Adult; D001364:Awareness; D016022:Case-Control Studies; D015897:Comorbidity; D003863:Depression / Q000150:complications; D003866:Depressive Disorder / Q000150:complications* / Q000503:physiopathology / Q000523:psychology*; D005239:Fear; D005260:Female; D006339:Heart Rate; D006801:Humans; D065812:Interoception; D008297:Male; D008875:Middle Aged; D010200:Panic; D016584:Panic Disorder / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D013315:Stress, Psychological / Q000150:complications / Q000503:physiopathology / Q000523:psychology*
keywords: Awareness; Depression; Interoception; Panic; Reactivity; Stress