The present proposal aims to fill a gap in the existing literature by developing theory and research on exposure to aversive life events and one's expectancies about those events, as applied to the etiology of panic disorder. The main purpose of the proposed research is to establish that the expectancy of anxiety in response to bodily sensations can result in acute emotional consequences akin to that commonly seen in panic disorder, and that such effects are potentiated when the onset of bodily stress is unpredictable compared to predictable. Anxiety expectancies will be experimentally manipulated before exposure to predictable and unpredictable episodes of bodily sensations. It is hypothesized that expectancies for anxiety will be associated with relatively more negative emotional consequences under conditions of unpredictable compared to predictable somatic perturbation. Additionally, it is hypothesized that an individual's preference for information regarding the onset of bodily perturbation is partially a function of the extent to which they expect somatic symptoms to elicit anxiety. The overall objective of this research program is to develop knowledge about the cognitive vulnerability processes of response expectancy and predictability as they apply to understanding the etiology of panic disorder.