Clinical versus nonclinical panic: a test of suffocation false alarm theory.

Klein's suffocation false alarm theory of panic implies that suffocation sensations should distinguish clinical from nonclinical panic attacks better than should other symptoms. To test this theory, we conducted phenomenologic comparisons between attack patterns of patients with panic disorder and community subjects who had experienced unexpected panic. Effect size and multivariate analyses revealed that three cognitive symptoms best discriminated clinical from nonclinical panic (fears of dying, heart attack, and loss of control). These findings are consistent with cognitive theories of panic. Although lacking the discriminative power of cognitive symptoms, suffocation sensations had the largest effect size of any physiological symptom. Accordingly, suffocation sensations may be especially likely to give rise to the catastrophic thoughts that best discriminate clinical from nonclinical panic.

Anxiety sensitivity and panic attacks in a nonclinical population.

In the present study, we administered the Anxiety Sensitivity Index (ASI) and a modified version of the Panic Attack Questionnaire (PAQ) to 425 college students to determine whether high anxiety sensitivity ('fear of fear') occurs in the absence of a history of unpredictable ('spontaneous') panic attacks, or whether such attacks are a necessary precursor to high anxiety sensitivity. Based on their ASI scores, subjects were assigned to either the high, medium, or low anxiety sensitivity groups. High anxiety sensitivity subjects more frequently reported both a personal and family history of panic than did subjects in the other groups. Nevertheless, two-thirds of the high anxiety sensitivity subjects had never experienced an unpredictable panic attack. This suggests that the fear of anxiety can be acquired in ways other than through personal experience with panic.

Anxiety sensitivity and history of panic as predictors of response to hyperventilation.

In this study, we examined the effects of anxiety sensitivity on the response to hyperventilation in college students with and without a history of spontaneous panic attacks. Reiss et al.'s (Behav. Res. Ther. 24, 1-8, 1986) Anxiety Sensitivity Index and Norton et al.'s (Behav. Ther. 17, 239-252, 1986) Panic Attack Questionnaire were used to select Ss. Following five min of voluntary hyperventilation, high anxiety sensitivity Ss reported more anxiety and more hyperventilation sensations than did low anxiety sensitivity Ss. A history of panic was only associated with enhanced responding to hyperventilation in Ss with high anxiety sensitivity; low anxiety sensitivity Ss who had experience with panic were no more responsive than low anxiety sensitivity Ss who had never had a panic attack. These findings suggest that high anxiety sensitivity may be a crucial determinant of panic attacks provoked by biological challenges (e.g. hyperventilation, sodium lactate infusion).