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

Epinephrine and fear of bodily sensations in panic disorder and social phobia

Fear of bodily symptoms of arousal has been implicated in the pathogenesis of both spontaneously occurring and experimentally provoked panic. Fear of bodily symptoms may be characteristic for panic disorder (PD) and is hypothesized to predict state anxiety and panic frequency during experimentally induced peripheral arousal. Twenty-eight subjects, 14 with PD and 14 with social phobia (SP) were infused with placebo and epinephrine (20, 40 and 80 ng/kg bodyweight/min) according to a fixed schedule in a single blind design. Fear of bodily symptoms was higher in subjects with PD, who also reported more bodily symptoms and higher state anxiety scores during the experiment. The panic rate (five out of 14), however, was the same in both groups. Panickers did not differ from non-panickers in trait- or baseline measures except for fear of bodily symptoms, which was marginally higher in panickers. Panickers showed greater reactivity in heart rate, diastolic blood pressure and capillary PCO(2). Our data do not support the hypothesis of a major role for fear of bodily symptoms in epinephrine-induced panic. Also, our results do not demonstrate a different reaction to epinephrine in PD and SP with situational panic attacks.

Anxiety sensitivity and panic attacks in an asthmatic population

The purpose of this study was to examine the relationship among anxiety sensitivity, the experience of frequent, spontaneous panic attacks, and pulmonary function in individuals with asthma. Ninety-three asthmatics participated by completing a battery of questionnaires and a spirometric assessment. Twenty-three percent of the asthmatics reported a history of spontaneous panic attacks with 9.7% reporting attacks that were severe and frequent enough to meet the DSM-IIIR criteria for panic disorder (PD). Anxiety sensitivity (ASI) scores, but not pulmonary function, was significantly related to PD. In addition, we compared the asthmatics (with and without PD) to 10 clinically diagnosed PD Ss without asthma and to 32 nonanxious, nonasthmatic controls on the ASI, the Body Sensations Questionnaire, and the Agoraphobic Cognitions Questionnaire. Whereas Ss with PD (asthmatic and nonasthmatic) displayed significant elevations on these measures compared to those without PD, the presence of asthma alone had no effect. The present study concurs with that of Porzelius et al. [Behaviour Research and Therapy, 30, 75-77 (1992)] in extending the validity of the cognitive model of PD to individuals with pulmonary disease.

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.

Panic attacks and interoceptive acuity for cardiac sensations

It has been suggested that perception of visceral changes, and cognitive reactions to such changes, may be important for triggering panic attacks. It remains to be determined, however, whether people with panic attacks are actually characterized by enhanced perceptual acuity for interoceptive stimuli. The purpose of this study was to explore the relationship between panic attacks and awareness for cardiac sensations using an objective heartbeat discrimination procedure. Twenty panickers and 20 nonpanickers were given 60 trials of the Whitehead heartbeat discrimination procedure. Thirty trials were given during rest and 30 following hyperventilation. Results indicated that panic attacks were not related to enhanced interoceptive acuity for cardiac sensations, either at rest or following hyperventilation. These results are discussed in terms of their relevance to cognitive models of panic.

Animal phobias versus claustrophobias: exteroceptive versus interoceptive cues

The overall purpose of this investigation was to examine heterogeneity among specific phobias. In particular, the goals were to compare features of fear responding between individuals fearful of claustrophobic situations and individuals fearful of spiders/snakes, and to compare their response to hyperventilation challenges. By so doing, specific predictions were tested in relation to a conceptual model of exteroceptive and interoceptive fear cues. Using a nonclinical sample, 19 subjects with spider/snake phobias, 18 nonphobics, and 9 subjects with claustrophobias were exposed on two separate occasions to a live tarantula or python, a small closet, and a hyperventilation challenge. Dependent measures included subjective anxiety, panic attacks, physical symptoms, cognitive symptoms (or, fear of symptoms) and heart rate. In addition, subjects completed a standardized self-report scale that measures fear of bodily symptoms of arousal. It was found that subjects with claustrophobia reported more physical symptoms and cognitive symptoms than did subjects with snake/spider phobias, in response to their fear-relevant stimulus. In addition, claustrophobic subjects were more fearful of hyperventilation challenges and reported more fear of bodily symptoms, than did snake/spider phobic subjects. Finally, subjects with claustrophobia were as fearful of hyperventilation as they were of their fear-relevant stimulus. Theoretical and empirical implications of these findings are discussed.

Effects of anxiety sensitivity on emotional response to a stress task

The purpose of this investigation was to further define the role of anxiety sensitivity, in relation to physiological arousal and the cognitive perception of anxiousness, as a determinant of anxiety. One hundred and thirty-two undergraduates at an urban university served as subjects. Two physiological measures of arousal and two cognitive measures of anxiety were used following an anxiety inducing task (mental arithmetic). The general expectation, which was supported, was that individual differences in anxiety sensitivity levels are more closely related to subjects' reported anxiousness in stressful conditions than are the actual physiological changes. Additionally, anxiety sensitivity was related to poststress levels of anxiety whereas trait anxiety was only related to pre- and postrelaxation levels of anxiety. Implications of the findings are addressed.

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.