The current study assessed the incremental prediction of anxiety sensitivity (AS) in both taxonic (categorical) and dimensional representations at various time points before and after a single vital capacity inhalation of a 35% CO(2), 65% balanced O(2) gas mixture. Participants were 128 young adults screened for a history of panic attacks. By controlling for traitwise factors including state anxiety and testing both categorical and continuous conceptualizations of the AS construct at various timepoints, the present report was able to evaluate the temporal and structural dynamics of AS in relation to fearful responding to the challenge. Relevant variables were evaluated in a hierarchical linear regression framework, and it was found that a continuous conceptualization of AS provided incremental predictive validity above and beyond trait anxiety immediately post-challenge, while a categorical representation of AS was equivalent to a continuous model of AS at post-challenge but outperformed a continuous model at follow-up. These data provide basic but important evidence suggesting that AS is uniquely associated with anxious responding to a 35% CO(2) challenge, and that categorical representations of AS should be considered in biological challenge studies.
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