title: Panic disorder and obsessive compulsive disorder in a hyperventilation challenge test.
abstract: BACKGROUND
  Stress-induced hyperventilation produces symptoms that people are prone to misinterpret as life-threatening if they are unaware of the consequences of overbreathing. Our aim was to observe the induction of panic attacks by a hyperventilation challenge test in a series of panic disorder and obsessive compulsive disorder (OCD) patients (DSM-IV).
  
  
  METHODS
  We randomly selected 28 panic disorder patients, 21 OCD patients and 28 normal volunteers. All patients were drug free for a week. They were induced to hyperventilate (30 breaths/min) for 4 min. Anxiety scales were applied before and after the test.
  
  
  RESULTS
  A total of 64.3% (n=18) panic disorder patients, 9.5% (n=2) OCD patients and 3.6% (n=1) of control subjects had a panic attack after hyperventilating (chi(2)=3.99, d.f.=2, P=0.026).
  
  
  CONCLUSIONS
  The hyperventilation challenge test has a low sensitivity for panic disorder.
  
  
  CONCLUSIONS
  In this challenge test the panic disorder patients were more sensitive to hyperventilation than OCD patients and normal volunteers. The induction of panic attacks by voluntary hyperventilation may be an easy test for validating the diagnosis in certain panic disorder patients.
authors.affiliation: Laboratory of Panic and Respiration, Federal University of Rio de Janeiro, R. Visconde de Pirajá, 407/702, 22410-003, Rio de Janeiro, Brazil. aenardi@novanet.com.br
authors.forename: Antonio Egidio
authors.initials: AE
authors.lastname: Nardi
authors.forename: Alexandre M
authors.initials: AM
authors.lastname: Valença
authors.forename: Isabella
authors.initials: I
authors.lastname: Nascimento
authors.forename: Walter A
authors.initials: WA
authors.lastname: Zin
mesh_terms: D000328:Adult; D001143:Arousal; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000523:psychology; D010200:Panic; D016584:Panic Disorder / Q000175:diagnosis* / Q000523:psychology; D011237:Predictive Value of Tests; D012016:Reference Values