Changes in respiration mediate changes in fear of bodily sensations in panic disorder

The purpose of the study was to examine whether changes in pCO2 mediate changes in fear of bodily sensation (as indexed by anxiety sensitivity) in a bio-behavioral treatment for panic disorder that targets changes in end-tidal pCO2. Thirty-five panic patients underwent 4 weeks of capnometry-assisted breathing training targeting respiratory dysregulation. Longitudinal mediation analyses of the changes in fear of bodily symptoms over time demonstrated that pCO2, but not respiration rate, was a partial mediator of the changes in anxiety sensitivity. Results were supported by cross lag panel analyses, which indicated that earlier pCO2 levels predicted later levels of anxiety sensitivity, but not vice versa. PCO2 changes also led to changes in respiration rate, questioning the importance of respiration rate in breathing training.The results provide little support for changes in fear of bodily sensations leading to changes in respiration, but rather suggest that breathing training targeting pCO2 reduced fear of bodily sensations in panic disorder.