Effects of threat context and cardiac sensitivity on fear responding to a 35% CO₂ challenge: A test of the context-sensitivity panic vulnerability model

The present study tested several predictions of a context-sensitivity panic vulnerability model emphasizing the interaction between threat context and threat sensitivities. Participants without a history of panic (N = 47) completed both global and domain-specific panic relevant sensitivity measures and were then randomized to undergo a 35% CO₂ inhalation challenge in the presence or absence of a cardiac defibrillator (threat context). As predicted by the model, cardiac sensitivity (but not trait anxiety or anxiety sensitivity) potentiated the effects of the presence of the defibrillator on CO₂ fear responding. Moreover, as predicted by the model, the observed potentiation effects of cardiac sensitivity on CO₂ fear responding were mediated by participants' threat appraisals connected to the presence of the defibrillator. Theoretical and clinical implications are discussed.