Relationships between the anxiety sensitivity index, the suffocation fear scale, and responses to CO2 inhalation

Interest in documenting ways to predict anxious responding in panic disorde r (PD) patients has proliferated recently in the literature. In the current study, two self-report measures were assessed to determine their relative utility in predicting responses to a panicogenic challenge. The Anxiety Sen sitivity Index (ASI) and the Suffocation Fear Scale (SFS) were evaluated by correlating scores on these measures with reactions to inhalation of 35% c arbon dioxide (CO2), assessed via anxiety ratings, panic symptom intensity, tidal volume (V-T) and respiratory rate (RR). A sample of 14 PD patients a nd 14 matched control (MC) participants demonstrated that the relationship between ASI scores and responses to 35% CO2 were stronger than the relation ship between SFS scores and responses to CO2. Specifically, both respirator y responses (V-T and RR) and self-reported reactions (anxiety and symptom i ntensity) were significantly correlated with scores on the ASI, In contrast , scores on the SFS were significantly correlated with only one measure of respiratory change (V-T). Although preliminary, these data indicate that th e ASI may be a more useful tool than the SFS in predicting self-reported an d respiratory responses to CO2 challenges. (C) 2001 Elsevier Science Inc. A ll rights reserved.