title: Panic attacks and perception of inspiratory resistive loads in chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Panic attacks are common in chronic obstructive pulmonary disease (COPD), and the prevalence of panic disorder is at least 10 times higher than in the general population. In the current study, we examined resistive load perception in patients with COPD with and without panic attacks.
  
  
  OBJECTIVE
  We tested competing hypotheses, based on conflicting results of earlier studies, that those patients with COPD with panic attacks or panic disorder would show either heightened or blunted perception of dyspnea as the magnitude of inspiratory resistive loads increased.
  
  
  METHODS
  We compared 20 patients with COPD with panic attacks or panic disorder, 20 patients without panic, and 20 healthy, age-matched subjects using an inspiratory resistive load-testing protocol.
  
  
  RESULTS
  We administered a diagnostic interview for panic attacks and panic disorder. We measured perceived dyspnea in response to increasing inspiratory resistive loads (modified Borg scale) and several respiratory variables. Dyspnea ratings increased linearly for all groups as the size of resistive loads increased. No significant differences were found between groups on the respiratory variables. Patients with COPD with panic attacks or panic disorder rated their level of dyspnea significantly higher than did other subjects.
  
  
  CONCLUSIONS
  Patients with COPD with panic attacks showed heightened sensitivity to inspiratory loads. The result reinforces the influence of psychological factors on symptom perception in this disease.
authors.affiliation: Department of Respiratory Medicine, Prince of Wales Hospital, Barker St., Randwick, NSW 2031, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Livermore
authors.forename: Jane E
authors.initials: JE
authors.lastname: Butler
authors.forename: Louise
authors.initials: L
authors.lastname: Sharpe
authors.forename: Rachel A
authors.initials: RA
authors.lastname: McBain
authors.forename: Simon C
authors.initials: SC
authors.lastname: Gandevia
authors.forename: David K
authors.initials: DK
authors.lastname: McKenzie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety; D004417:Dyspnea / Q000150:complications / Q000523:psychology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D001239:Inhalation; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000150:complications*; D010465:Perception; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000523:psychology*; D014797:Vital Capacity; D014939:Work of Breathing