title: Comorbid depressive disorder increases vulnerability to the 35% carbon dioxide (CO2) challenge in panic disorder patients.
abstract: BACKGROUND
  The hypothesis of this study was that panic disorder patients with a comorbid depressive disorder would be less vulnerable to the 35% CO2 panic provocation challenge than panic disorder patients without a comorbid depressive disorder. This hypothesis was based on findings from ventilatory response studies in depressive patients.
  
  
  METHODS
  Twelve panic disorder patients with and 23 panic disorder patients without a comorbid depressive disorder were challenged.
  
  
  RESULTS
  Panic disorder patients with a comorbid depressive disorder scored significantly higher on ratings of subjective anxiety and panic symptoms induced by the challenge.
  
  
  CONCLUSIONS
  A comorbid depressive disorder appeared to increase the vulnerability of panic disorder patients to this panic provocation.
  
  
  CONCLUSIONS
  We did find significant differences, but these differences did not confirm the original hypothesis.
  
  
  CONCLUSIONS
  Our results support clinical data that show that a comorbid depressive disorder correlates with an increased severity of panic disorder.
authors.affiliation: Dept. of Psychiatry and Neuropsychology, Academic Psychiatric Center, Maastricht University, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Verburg
authors.forename: T
authors.initials: T
authors.lastname: Klaassen
authors.forename: H
authors.initials: H
authors.lastname: Pols
authors.forename: E
authors.initials: E
authors.lastname: Griez
mesh_terms: D000328:Adult; D001007:Anxiety; D002245:Carbon Dioxide / Q000008:administration & dosage; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology / Q000523:psychology*; D005260:Female; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D016584:Panic Disorder / Q000453:epidemiology / Q000523:psychology*; D012720:Severity of Illness Index
chemical_list: D002245:Carbon Dioxide