The absence of relation between anxiety sensitivity and fear conditioning using 20% versus 13% CO2-enriched air as unconditioned stimuli

Anxiety sensitivity has been implicated as a risk factor in the development and maintenance of anxiety and fear-related disorders. Indeed, persons who score high on the anxiety sensitivity index (ASI) are generally more respo nsive to biological challenge procedures such as CO2-inhalation that direct ly evoke the feared bodily events. One would expect, therefore, that person s high on anxiety sensitivity should be more conditionable and hence more l ikely to acquire fears, than persons low on anxiety sensitivity when CO2-en ricbed air is used as an unconditioned stimulus (UCS). Undergraduates (N = 96), scoring high, medium and low on the ASI received 8 repeated 20-s inhal ations of either 20 or 13% CO2-enriched air (UCSs) paired with one of three CSs differing in fear-relevance (snake, heart and flowers). Several autono mic and self-report measures were assessed. Contrary to expectation, electr odermal and cardiac conditioned responses failed to discriminate between AS I groups. Yet, SUDS and severity and frequency of DSM-IV panic symptoms var ied reliably as a function of anxiety sensitivity. Overall, the findings su ggest that anxiety sensitivity is related to subjective fear-related compla ints, but not autonomic responding and conditionability. We discuss clinica l and theoretical implications for understanding the place of anxiety sensi tivity in fear onset. (C) 1998 Elsevier Science Ltd. All rights reserved.