Physiological markers for anxiety: Panic disorder and phobias

We developed a capnometry feedback assisted breathing training therapy for panic disorder designed to reduce hyperventilation and making breathing regular. Without feedback, conventional therapeutic breathing instructions may actually increase hyperventilation by increasing dyspnea. Five weekly therapy sessions accompanied by daily home practice with a capnometer produced marked clinical improvement compared to changes in an untreated group. Improvement was sustained over a 12-month follow-up period. The therapist avoided any statements or procedures designed to alter cognitions. Improvement occurred regardless of whether patients initially reported mostly respiratory or non-respiratory symptoms during their attacks. There is evidence that modifying any of the three systems comprising a fear network can be therapeutic, as exemplified by cognitive therapy modifying thoughts, exposure therapy modifying avoidance, and breathing training procedures modifying pCO2.