E-Mail karger@karger.com Review Neuropsychobiology 2014;70:52–60 DOI: 10.1159/000364830 Are Respiratory Abnormalities Specific for Panic Disorder? A Meta-Analysis Massimiliano Grassi a Daniela Caldirola a Nunzia Valentina Di Chiaro a Alice Riva a Silvia Daccò a Maurizio Pompili b Giampaolo Perna a, c, d a Department of Clinical Neurosciences, Villa San Benedetto Hospital, Hermanas Hospitalarias, FoRiPsi, Albese con Cassano, and b Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy; c Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, University of Maastricht, Maastricht, The Netherlands; d Leonard M. Miller School of Medicine, University of Miami, Miami, Fla., USA ties 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 cogni- tive/emotional/behavioral factors in this population. © 2014 S. Karger AG, Basel Introduction A link between panic disorder (PD) and respiration is well established. The presence of prominent respiratory symptoms during panic attacks, the behavioral and respi- ratory hypersensitivity to hypercapnic gas mixture-inha- lation in patients with PD, and a specific bidirectional as- sociation between PD and respiratory diseases support this link [1, 2]. Several theories sharing the idea of a caus- al relationship between aberrant respiratory regulation and panic have been developed [2–5], even though the nature of this respiratory abnormality is not yet fully un- derstood. We recently performed a meta-analysis of studies that compared PD and control groups on baseline respiratory variables and hematic variables related to the respiratory function [6]. We found higher baseline mean minute ventilation (MV), lower end-tidal partial pressure of CO 2 Key Words Panic attacks · Social phobia · Anxiety disorders · Affective disorders · Biological psychiatry Abstract Objectives: There is evidence of baseline respiratory abnor- malities 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 respira- tory and hematic variables between subjects with PD and subjects with other anxiety disorders. Methods: A literature search in bibliographic databases was performed. Fixed-ef- fects 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 re- sults support the idea that baseline respiratory abnormali- Received: February 17, 2014 Accepted after revision: May 24, 2014 Published online: September 19, 2014 Daniela Caldirola, PhD, MD Department of Clinical Neurosciences Villa San Benedetto Hospital, Hermanas Hospitalarias, Via Roma 16 IT–22032, Albese con Cassano (Italy) E-Mail caldiroladaniela  @  gmail.com © 2014 S. Karger AG, Basel 0302–282X/14/0701–0052$39.50/0 www.karger.com/nps Downloaded by: Universiteit Maastricht 137.120.4.50 - 10/28/2014 1:04:40 PM