Mediators of Change in Capnometry Guided Respiratory Intervention for Panic Disorder.
Capnometry guided respiratory interventions have shown promising results in the treatment of panic disorder, but mechanisms of change are not yet well-understood. The current study examined changes in end-tidal carbon dioxide (ETCO2), anxiety sensitivity, and perceived control as mediators of panic symptom change. Sixty-nine adults with panic disorder received 4 weeks of respiratory training, and panic symptom severity and potential mediators were assessed at Pre-treatment, Mid-treatment, Post-treatment, 2-month follow-up, and 12-month follow-up. Multilevel mediation analyses showed that changes in perceived control significantly mediated changes in panic disorder severity and that for individuals who were hypocapnic at pre-treatment, ETCO2 was a significant mediator of symptom outcome. Findings provide further evidence that changes in perceived control, and improvements in respiratory dysregulation for hypocapnic individuals specifically, underlie symptom improvement from capnometry guided respiratory intervention for panic disorder.