Subjective symptoms and cardiac reactivity to brief hyperventilation in individuals with high anxiety sensitivity

Cognitive models maintain that panic attacks may be initiated by fear resulting from the interpretation of somatic sensations as personally threatening or harmful. Similarly, several researchers have proposed that the enhanced response of panickers to biological challenge may result from the fear of induced anxiety sensations rather than from direct stimulation of aberrant biochemical systems. The present study examined the effects of both panic history and fear of anxiety sensations on subjective and cardiac responses to biological challenge. Eighty nonclinical subjects were chosen on the basis of level of anxiety sensitivity and history of previous panic attacks. High and low anxiety-sensitive panickers and nonpanickers (four groups of 20 subjects) were subjected to a 90 sec period of voluntary hyperventilation, during which heart rate was assessed. Regardless of panic history, total symptom scores did not differ between high and low anxiety-sensitive subjects at baseline or pre-hyperventilation, but did differ at post-hyperventilation. There were, however, no significant differences in post-hyperventilation measures of heart rate. The apparent mismatch of subjective and physiological responsivity to the challenge in high anxiety-sensitive individuals (i.e. more severe symptom self-reports in the absence of increased cardiac activation) provides support for the hypothesis that high anxiety sensitivity is associated with an enhanced tendency to panic in response to biological challenge.