Unexpected arousal, anxiety sensitivity, and their interaction on CO2-induced panic: Further evidence for the context-sensitivity vulnerability model

The present experiment tested several predictions derived from the context-sensitivity vulnerability model of panic. Participants (N = 79) scoring either high or low in anxiety sensitivity (AS) and with no history of unexpected panic were randomly assigned to one of two instructional sets: expected arousal (EA) or expected relaxation (ER). All participants were administered inhalation of room air and 35% CO2 in a counterbalanced order. Consistent with theoretical predictions, High-AS participants who received ER instructions showed greater emotional responding compared to High-AS participants who received EA instructions, while instructional set did not affect responding among Low-AS participants. Panic attacks were observed in 52% of the High-AS-ER group compared to 17%, 5%, and 5% in the High-AS-EA, Low-AS-ER, and Low-AS-EA groups respectively. These findings are consistent with the theory's assertion that dispositional tendencies, such as anxiety sensitivity potentiate the panicogenic effects of threat-relevant context variables.

► This experiment tested predictions from the context-sensitivity model of panic.
► Subjects’ high in anxiety sensitivity (AS) were more likely to show greater fear responding to 35% CO2 inhalation relative to subjects low in anxiety sensitivity, however this relationship was strongly moderated by the experimental manipulation of threat context.
► High AS subjects who were led to expect that 35% CO2 inhalation would produce feelings of relaxation showed markedly greater fear and probability of panic relative to High AS subjects who were led to expect heightened arousal.
► As predicted, subjects low in AS were unaffected by the manipulation of the “unexpectedness” of CO2 effects.
► These findings provide additional support for the role of context in moderating the effects of anxiety sensitivity on fear responding to biological challenge.