Affective responses to hyperventilation: a test of the cognitive model of panic

A cognitive explanation of the association between acute hyperventilation and panic attacks has been proposed: the extent to which sensations produced by hyperventilation are interpreted in a negative and catastrophic way is said to be a major determinant of panic. Non-clinical subjects were provided with a negative or a positive interpretation of the sensations produced by equivalent amounts of voluntary hyperventilation. As predicted, there was a significant difference between positive and negative interpretation conditions on ratings of positive and negative affect. Subjects in the positive interpretation condition experienced hyperventilation as pleasant, and subjects in the negative interpretation condition experienced hyperventilation as unpleasant, even though both groups experienced similar bodily sensations and did not differ in their prior expectations of the affective consequences of hyperventilation. When the subjects were given a positive interpretation, the number of their sensations correlated with positive affect; when a negative interpretation was given, the number of bodily sensations correlated with negative affect. The results provide support for a cognitive model of panic and are inconsistent with the view that panic is simply a symptom of hyperventilation syndrome.     

The hyperventilation syndrome in panic disorder, agoraphobia and generalized anxiety disorder

The symptom complex of panic disorder and generalized anxiety disorder suggests an etiological role for hyperventilation. The present study investigates the overlap between DSM-III-R panic disorder, panic disorder with agoraphobia and generalized anxiety disorder with hyperventilation syndrome (HVS). The anxiety disorder diagnoses were based on a structured interview, and HVS syndrome (HVS). The anxiety disorder diagnoses were based on a structured interview, and HVS determined by the so-called hyperventilation provocation test (a brief period of voluntary hyperventilation with recognition of symptoms). The overlap rates with HVS were: 48% for panic disorder, 83% for panic disorder with agoraphobia and 82% for generalized anxiety disorder. However, a pilot study on transcutaneous monitoring of carbon dioxide tension leads us to question the validity of the voluntary hyperventilation method that we used to determine HVS-status. It is unclear whether hyperventilation plays an important role in panic and general anxiety, as our overlap findings suggest. For patients who recognize the symptoms induced by voluntary hyperventilation, the hyperventilation provocation procedure provides a therapeutic means of exposure to feared bodily sensations.     

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).     

Evaluating panic-specific factors in the relationship between suicide and panic disorder

Work during the past decade has suggested an association between panic disorder and suicide (i.e., suicidal ideation and suicide attempts) that cannot simply be accounted for by co-occurring depression symptoms. To clarify the linkage between panic disorder and suicide, the association between panic-specific clinical and cognitive variables and suicide indicators were evaluated in patients with panic disorder (N=146). Analyses predicting the presence of suicidal ideation (positive, negative) after covarying the effects of a current mood disorder diagnosis and depression symptoms indicated a number of significant predictors including: (1) overall anxiety symptoms; (2) level of anticipatory anxiety; (3) avoidance of bodily sensations; (4) attentional vigilance toward bodily perturbations; and (5) phrenophobia (i.e., fear of cognitive incapacitation). Anxiety-specific variables did not account for unique variance in predicting prior history of suicide attempts.     

The Interactive Role of Anxiety Sensitivity and Pubertal Status in Predicting Anxious Responding to Bodily Sensations among Adolescents

The present study examined the interaction between pubertal status and anxiety sensitivity (AS) in predicting anxious and fearful responding to a three-minute voluntary hyperventilation challenge among 124 (57 females) adolescents between the ages of 12 and 17 years (Mage = 15.04; SD = 1.49). As predicted, after controlling for baseline anxiety, age, and gender, there was a significant interaction between pubertal status and AS in predicting anxious responding to bodily sensations to the hyperventilation challenge. Specifically, adolescents reporting more advanced pubertal status and higher levels of AS reported the greatest post-challenge self-reported anxiety focused on bodily sensations, whereas pubertal status had relatively less of an effect on low AS adolescents. A test of specificity also was conducted; as expected, the interaction between AS and pubertal status was unrelated to generalized negative affectivity, suggesting the predictor variables interact to confer specific risk for anxious responding to bodily sensations. Finally, exploratory analyses of psychophysiological reactivity to the challenge indicated AS, but not pubertal status, moderated the relation between challenge-related change in heart-rate and post-challenge anxiety such that high AS youth who had experienced a relatively greater heart-rate change reported the most anxious reactivity to the challenge. Results are discussed in relation to theory regarding vulnerability to anxious responding to bodily sensations among adolescents.     

Panic symptoms in asthma and panic disorder: a preliminary test of the dyspnea-fear theory.

Ley's (Behaviour Research and Therapy, 27, 549-554, 1989) dyspnea-fear theory was tested on three groups of subjects: 10 with panic disorder, 24 with asthma, and 12 who were nonanxious and nonasthmatic, using measures of pulmonary function, muscle tension; and self-report measures of generalized anxiety, dyspnea, and psychopathology. Results are supportive of dyspnea-fear theory for asthmatics but not for individuals with panic disorder. Differences between groups on panic/fear measures were explained by a combination of general anxiety and dyspnea. Within-group regression analyses showed that only generalized anxiety symptoms contributed significantly to scores on the Asthma Symptom Checklist scale of panic/fear within the panic disorder group; while only dyspnea contributed to panic/fear among asthmatics. Additional results show that panic disorder subjects performed normally on pulmonary function tests but reported respiratory symptoms as severe as did asthmatics. Compared with normal subjects, both patient groups displayed lower correlations between self-rated symptoms of bronchoconstriction and objective pulmonary measures. Panic disorder subjects showed a negative relationship between pulmonary function and hyperventilation symptoms, suggesting a heightened sensitivity to, and discomfort with, sensations associated with normal pulmonary function. Asthmatics displayed a significant relationship between degree of airway obstruction and both trapezius surface EMG and ratings of hyperventilation symptoms.     

The catastrophic misinterpretation of physiological distress.

Cognitive theories of panic disorder suggest that the catastrophic misinterpretation of bodily sensations is the trigger for a panic attack. A challenge to cognitive theories is the suggestion that dyspnea (shortness of breath) is central to the development of panic and that negative cognitions are by-products of panic. To examine these seemingly contradictory theoretical perspectives, the present study investigated panic symptomatology in a sample of patients with chronic shortness of breath (i.e. pulmonary patients). Past studies have shown an increased prevalence of panic in pulmonary patients, a finding that may be useful in elucidating panic etiology. The current sample of pulmonary patients (N = 28) confirmed previous reports of high prevalence rates of panic in this population. Based on self-report of panic symptomatology, a total of nine patients (32%) met DSM-IV criteria that were consistent with panic disorder. Multivariate comparison of participants with and without panic symptomatology revealed that panickers had significantly higher levels of anxiety, depression and agoraphobic cognitions. However, these groups showed no significant differences on physiological measures of pulmonary functioning. The authors conclude that dyspnea alone is inadequate in predicting panic development. High levels of panic symptomatology in pulmonary samples may reflect increased opportunities for these patients to misinterpret bodily sensations and, in particular, their pulmonary symptoms.     

Breathing retraining, exposure and a combination of both, in the treatment of panic disorder with agoraphobia

The present study investigates the differential effectiveness of three treatment packages for agoraphobia. Patients suffering from panic disorder with agoraphobia (DSM-III-R) received one of three treatments: Breathing Retraining with Cognitive Restructuring (BRCR), graded self-exposure in vivo (EXP), or a combination of BRCR and EXP. Treatments consisted of 8 sessions. Assessments consisted of self-report measures for panic, phobic anxiety and avoidance, depression, general anxiety, somatic complaints and fear of bodily sensations, and of two respiratory measures (respiratory rate and alveolar pCO₂).

The treatments resulted in a reduction in symptomatology on all self-report measures, except panic frequency, and in a decrease in respiratory rate. There was no evidence for a differential efficacy for any of the treatments on any of the variables. Contrary to expectation, and at odds with findings from earlier studies, BRCR had no significant effect on panic frequency. A detailed comparison of sample characteristics of patients in our study and previous studies, did not yield insight into possible causes for the failure to replicate earlier results. The limited effectiveness of breathing retraining in reducing panic, as observed in the present study, leads us to conclude that the role of hyperventilation in panic is less important than previously thought.     

Discomfort intolerance: evaluation of a potential risk factor for anxiety psychopathology

Discomfort intolerance, defined as an individual difference in the capacity to tolerate unpleasant bodily sensations, is a construct recently posited as a risk factor for panic and anxiety psychopathology. The present report used a biological challenge procedure to evaluate whether discomfort intolerance predicts fearful responding beyond the effects of trait anxiety and a well-established psychological vulnerability factor (i.e., anxiety sensitivity). Nonclinical community participants (N=44) with no history of panic attacks or any Axis I condition completed a 35% CO(2) challenge. Results are consistent with our hypothesis suggesting that discomfort intolerance incrementally predicts increased subjective reactivity to the challenge. Moreover, there was some suggestion that discomfort intolerance interacted synergistically with anxiety sensitivity to increase anxiety-related symptoms. These findings add to a small but growing literature suggesting that discomfort intolerance may play a role in the development of anxiety problems.     

Social anxiety and fear of bodily sensations in panic disorder and agoraphobia: A matched comparison

This study tests the hypothesis that social anxiety and fear of bodily sensations are associated with the development of agoraphobic avoidance behavior in panic disorder patients. Twenty patients with panic disorder were compared to 20 patients with panic disorder with agoraphobia, matched by sex and duration of disorder. The two groups did not differ on measures of fear and frequency of assertive social responses. However, the agoraphobics scored higher on measures of interpersonal sensitivity, depression, feelings of inadequacy, and hostility. They also reported higher fear of bodily sensations. Although definitive conclusions need to be postponed until prospective studies have been conducted, there is evidence suggesting that the development of agoraphobia in panic patients is associated with hypersensitivity to bodily sensations and interpersonal situations.This research was supported by Grant 560-268-009 of the Dutch Organization for Scientific Research.     

Effects of aerobic exercise on anxiety sensitivity

Anxiety sensitivity is a known precursor to panic attacks and panic disorder, and involves the misinterpretation of anxiety-related sensations. Aerobic exercise has been shown to reduce generalized anxiety, and may also reduce anxiety sensitivity through exposure to feared physiological sensations. Accordingly, 54 participants with elevated anxiety sensitivity scores completed six 20-min treadmill exercise sessions at either a high-intensity aerobic ( n = 29 ) or low-intensity ( n = 25 ) level. Self-ratings of anxiety sensitivity, fear of physiological sensations associated with anxiety, and generalized anxiety were obtained at pre-treatment, post-treatment, and one-week follow-up. Results indicated that both high- and low-intensity exercise reduced anxiety sensitivity. However, high-intensity exercise caused more rapid reductions in a global measure of anxiety sensitivity and produced more treatment responders than low-intensity exercise. Only high-intensity exercise reduced fear of anxiety-related bodily sensations. The implications of these findings are discussed.     

Negative content of thinking in panic disorder and major depression–a self-report study

The purpose of the present study was to investigate the character and extent of negative thought content in panic disorder (PD) and the relation between thinking and bodily sensations. Content of thinking was explored in several areas, some of which are not exclusively related to anxiety. A structured diagnostic interview (SCID), a self-rating scale (SCL-90R), a sentence construction test (The Incomplete Sentences Blank (ISB)), and an inventory of childhood memories of parental rearing (the EMBU) were administered to 47 PD patients, 15 patients with major depression (MD), and 30 normal subjects. Thus, measures of implicit as well as explicit thinking, measures of thinking on present as well as past issues, and methods allowing negative as well as positive thought content to be expressed, were used. We found that PD was characterized by more negative thinking of anxiogenic, depressive, and dependent nature and less neutral or positive thinking than the normal subjects, primarily in issues related to the present. These negative thoughts were correlated with bodily symptoms. Very few significant differences were found between PD and MD, but a subgroup of PD with comorbidity of MD exceeded the other groups on measures of negative thoughts as well as bodily symptoms.     

The hyperventilation provocation test in panic disorder.

Forty-eight patients with DSM-III-R Panic Disorder underwent a hyperventilation provocation Test (HVPT). Twenty-four patients rated the symptoms induced during the HVPT as similar to those occurring during panic attacks in daily life. Contrary to the classical hyperventilation model of panic, no differences were found in respiratory physiology between recognizers and non-recognizers before and during voluntary hyperventilation. Moreover, recognizers and non-recognizers reported comparable levels of panic and hyperventilation symptoms and state anxiety during panic attacks in daily life. Ten of the recognizers also had a panic attack during the HVPT, independent of any differential CO2 alterations. Compared to non-panickers, panickers obtained higher scores for agoraphobia and depression. On the basis of these results, it is concluded that recognizers or panickers do not show a tendency towards hyperventilation, but that reports of severe panic and hyperventilation symptoms are more closely related to the level of anxiety. These results are more consistent with the cognitive model of panic, which emphasizes the patient's tendency to interpret somatic symptoms catastrophically.     

Anticipation of interoceptive threat in highly anxiety sensitive persons

Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context.     

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 nonphobies, 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.     

Panic disorder: A product of classical conditioning

Contrary to the common view that all panic attacks have a single etiology, it is shown that a distinction must be made between initial attacks, for which there are many causes, and recurrent attacks (panic disorder) which have a common basis. Most initial panic attacks are attributable to the physiological effects of hyperventilation resulting from severe and prolonged anxiety. It has been claimed that the attacks are due to such symptoms as dyspnea, tachycardia and dizziness being misattributed to deadly illness or incipient insanity. We reject this view on several grounds, and in particular because of a pilot study that showed that such attributions follow the onset of panic. Apart from some biological cases, the common initial panic is an unconditioned response to a bizarre stimulus complex produced by excessive hyperventilation, and panic disorder is the result of contiguous stimuli, especially endogenous stimuli, being conditioned to the elicited anxiety. Treatment accords with principles of conditioning.     

Cognitive therapy versus interoceptive exposure as treatment of panic disorder without agoraphobia

Cognitive therapy (CT) and interoceptive exposure (IE) as treatments of panic disorder without agoraphobia were compared in a sample of 69 patients, randomly allocated to condition. There were no significant differences between treatments as to reductions in panic frequency, daily anxiety levels and a composite questionnaire score, at posttest after the 12-session treatment, and at both follow-ups (4 weeks, 6 months). In both conditions, high percentages of patients were panic free at post and follow-up tests (range 75-92%). Although the reduction in idiosyncratic beliefs about the catastrophic nature of bodily sensations was equally strong in both conditions, post-treatment beliefs correlated strongly with symptoms at post and follow-up tests in the CT condition, but not in the IE condition. Reduction of beliefs may be essential in CT, but not in IE. This suggests that the two treatments utilize different change mechanisms.     

Respiratory function, cognitions, and panic in chronic obstructive pulmonary patients.

The present study investigated the relationship between respiratory function, catastrophic thoughts about anxiety, and panic in 48 Chronic Obstructive Pulmonary Disease (COPD) patients. During a routine office visit which included respiratory function tests (Forced Vital Capacity, FVC; Forced Expiratory Volume--first second, FEV1) patients completed a battery of questionnaires which assessed history of panic, days with shortness of breath, general activity level, agoraphobic cognitions, perception of bodily sensations, anxiety and depression. Thirty-seven percent of the sample reported experiencing a panic attack. Subjects showed a significant impairment in respiratory functioning. Patients with a history of panic did not differ from those who had not experienced panic on demographic, physiologic, or activity variables. Patients who experienced panic reported significantly more agoraphobic cognitions and greater concern with bodily sensations than did patients who did not experience panic.     

An examination of the relation between traumatic event exposure and panic-relevant biological challenge responding among adolescents

The current study uniquely extended research that has linked traumatic event exposure to panic-spectrum problems among adolescents. It was hypothesized that among 127 adolescents (age range: 10 to 17 years; M = 14.63, SD = 2.24), those who endorsed a history of traumatic event exposure would evidence significantly greater anxious and fearful reactivity to a well-established 3-min voluntary hyperventilation procedure compared to nonexposed individuals. Results were consistent with hypotheses, suggesting traumatic event exposure is associated with anxious and fearful reactivity to abrupt increases in bodily arousal among adolescents. Moreover, consistent with hypotheses, anxiety sensitivity significantly mediated the relations between traumatic event exposure and both self-reported panic symptoms and panic symptoms elicited by the challenge. Future prospective research is now needed to better understand temporal relations between traumatic event exposure and indices of panic and related vulnerability.     

Anxiety sensitivity and perceived control over anxiety-related events: evaluating the singular and interactive effects in the prediction of anxious and fearful responding to bodily sensations

The present investigation examined the singular and interactive effects of anxiety sensitivity and perceived control over anxiety-related events in the prediction of panic symptoms using a CO(2)-enriched air biological challenge. Two hundred and twenty-nine adult participants (M(age)=21.02, SD=7.55, 124 females) were recruited from the greater Burlington, Vermont community. Results indicated that pre-challenge anxiety sensitivity, but not perceived control over anxiety-related events, significantly predicted post-challenge panic attack symptoms, anxiety focused on bodily sensations, and, interest in returning for another challenge (behavioral avoidance). In regard to physiological findings, anxiety sensitivity was significantly related to skin conductance level whereas perceived control over anxiety-related events was related to respiration rate. Neither anxiety sensitivity nor perceived control over anxiety-related events was related to heart rate. There also were no interactive effects between anxiety sensitivity and perceived control over anxiety-related events for any of the studied dependent variables. Results are discussed in relation to multi-risk factor models of cognitive vulnerability for panic psychopathology.