Psychological and physiological predictors of response to carbon dioxide challenge in individuals with panic disorder

Past studies in nonclinical samples have found that suffocation fear, but not a behavioral index of carbon dioxide (CO₂) sensitivity (i.e., breath-holding duration), predicts anxious response to CO₂ challenge. These associations were examined in individuals with panic disorder while adding more sensitive indices of CO₂ sensitivity. Consistent with the earlier studies, the authors found that suffocation fear predicted anxious responding to CO₂ challenge but breath-holding duration did not. However, highly precise measures of CO₂ sensitivity, not included in earlier studies, did predict anxious challenge responding. These findings support the predictive value and possible etiological relevance of both specific psychological variables and physiological CO₂ sensitivity in panic vulnerability. Further work is still needed to determine whether the findings are specific to panic disorder.