Co₂ inhalation in the treatment of panic attacks

If panic disorder is conceptualized as a fear of interoceptive sensations, it can be treated by exposure to the autonomic symptoms that are induced by CO₂ inhalation. In a cross-over study of 14 patients, propranolol was used as a control treatment. CO₂ produced a significant reduction of fear of autonomic panic sensations, state and trait anxiety, agoraphobic anxiety and avoidance, and of the frequency of panicking. Propranolol resulted in improvements of state and of agoraphobic anxiety. Except for Trait Anxiety, CO₂ was superior on all measures, most clearly on the Fear of Autonomic Sensations. At the 6-month follow-up, 3 patients required further treatment. Except for State Anxiety, the improvements were, on average, maintained. The clinical and theoretical implications are discussed.