title: Are respiratory abnormalities specific for panic disorder? A meta-analysis.
abstract: OBJECTIVE
  There is evidence of baseline respiratory abnormalities in panic disorder (PD), but whether they are specific to PD remains unclear. To investigate this issue, we meta-analyzed results from studies comparing baseline respiratory and hematic variables between subjects with PD and subjects with other anxiety disorders.
  
  
  METHODS
  A literature search in bibliographic databases was performed. Fixed-effects models were applied. Several moderator analyses and publication bias diagnostics were performed.
  
  
  RESULTS
  We found: (1) significantly lower mean end-tidal partial pressure of CO(2) (et-pCO(2)) in subjects with PD than in those with social phobia (SP) or generalized anxiety disorder (GAD), and (2) higher mean respiratory rate, lower venous et-pCO(2) and HCO(3)(-) concentration in subjects with PD than in those with SP. No publication bias was found.
  
  
  CONCLUSIONS
  Subjects with PD show a condition of baseline hyperventilation when compared to subjects with SP or GAD. Hematic variables suggest that the hyperventilation may be chronic. These results support the idea that baseline respiratory abnormalities are specific to PD pathophysiology. Further studies are needed to clarify whether these abnormalities are related to a malfunction of the respiratory system or to specific cognitive/emotional/behavioral factors in this population.
authors.affiliation: Department of Clinical Neurosciences, Villa San Benedetto Hospital, Hermanas Hospitalarias, FoRiPsi, Albese con Cassano, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Grassi
authors.forename: Daniela
authors.initials: D
authors.lastname: Caldirola
authors.forename: Nunzia Valentina
authors.initials: NV
authors.lastname: Di Chiaro
authors.forename: Alice
authors.initials: A
authors.lastname: Riva
authors.forename: Silvia
authors.initials: S
authors.lastname: Daccò
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pompili
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Perna
mesh_terms: D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans; D016584:Panic Disorder / Q000150:complications*; D012120:Respiration Disorders / Q000175:diagnosis / Q000209:etiology*