Detection of somatic sensations in panic disorder

Twenty-four panic disorder patients and 25 nonclinical subjects underwent double-breath inhalations of 5, 10, and 20% carbon dioxide (CO₂) or room air. All subjects were blind to inhalation content and were required to guess if the inhalation contained CO₂. There was no significant difference between groups in the accuracy with which they were able to detect CO₂ at any concentration. Similarly, the number of somatic symptoms reported to each inhalation did not differ between groups. The findings question suggestions that individuals with panic disorder are more accurate at detecting changes in physiology than other individuals.     

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.     

Nocturnal panic: response to hyperventilation and carbon dioxide challenges

To examine the role of ventilatory response in nocturnal panic, subjects experiencing nocturnal panic were compared with those who experienced daytime panic attacks only. In particular, measures of chronic hyperventilation (baseline pCO2) and CO2 hypersensitivity (response to ventilatory challenges) were assessed. Subjective and psychophysiological measures were obtained during baseline, forced hyperventilation, and carbon dioxide inhalation phases of a standardized laboratory-based assessment. The groups did not differ with respect to subjective or physiological measures or to the frequency with which panic occurred during the assessment. The results do not lend support to models that emphasize central CO2 hypersensitivity and chronic hyperventilation as primary mechanisms underlying nocturnal 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).     

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.     

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 role of hyperventilation in panic disorder: a response to Ley (1991)

Ley (Behaviour Research and Therapy, 29, 301–304, 1991) provided a reinterpretation of experimental findings on the efficacy of breathing retraining plus cognitive restructuring in reducing the symptomatology of patients with panic disorder with agoraphobia which were presented in a 1989 article in this journal. On the basis of his reinterpretation, they concluded that our findings supported the central role of hyperventilation in panic attacks. Ley's arguments are discussed and we conclude that his reinterpretation provides new arguments against a hyperventilation theory of panic. Furthermore, recent evidence from empirical studies does not support a central role for hyperventilation in panic attacks.     

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.     

The efficacy of breathing retraining and the centrality of hyperventilation in panic disorder: a reinterpretation of experimental findings

The present paper addresses de Ruiter, Rijken, Garssen, and Kraaimaat's (Behaviour Research and Therapy, 27, 647-655, 1989) interpretation of data pertaining to the efficacy of breathing retraining in the treatment of panic disorder. The proffered reinterpretation of these data makes it clear that breathing retraining led to a significant reduction in the frequency of panic attacks. These findings thus lend additional support to the central role of hyperventilation in primary panic attacks.     

Introspective awareness of sensations

My goal is to formulate a theory of introspection that can be integrated with a strongly reductionist account of sensations that I have defended elsewhere. In pursuit of this goal, I offer a skeletal explanation of themetaphysical nature of introspection and I attempt to resolve several of the main questions about theepistemological status of introspective beliefs.I owe a large debt to Sydney Shoemaker. I have been helped considerably both by conversations with him and by the lectures he gave in the summer of 1985 in his N.E.H. Summer Seminar on Self-Consciousness and Self-Reference. I have also received valuable advice from Richard Lee, David Roach, David A. Schroeder, Lynne Spellman, and (especially) Anthony L. Brueckner, Willem de Vries, and David H. Westendorf.     

Cognitive suppression of tilt sensations during linear horizontal self-motion in the dark

On the basis of models of otolith functioning, one would expect that, during sinusoidal linear self-motion in darkness, percepts of body tilt are experienced. However, this is normally not the case, which suggests that the otoliths are not responsive to small deviations from the vertical of the gravito-inertial force vector acting on them. Here we show that this is incorrect. Subjects usually know on what kind of linear motion device they are (going to be) moved, having seen it prior to experimentation. This may result in a cognitive suppression of such otolith responses. In the present study, subjects were kept completely unaware of how they were moved and were asked to report on how they thought they moved. About 50% of the reports included tilt percepts almost immediately. It is concluded that this reveals the presence of otolith responsiveness to even small and short-lived deviations of the gravito-inertial force vector from verticality, a responsiveness which is suppressed when (prior) cognitions exist that the motion path is purely in the horizontal plane.     

Presleep attributions about arousal during sleep: nocturnal panic

This study examined the role of presleep attributions about physiological events during sleep in nocturnal panic attacks. Patients who regularly experienced nocturnal panic were physiologically monitored as audio signals were presented during sleep. They were randomly assigned to 1 of 3 conditions: expected, in which signals of intense physiological changes were expected; unexpected, in which signals of intense physiological changes were not expected; or control, involving distinctly different signals unrelated to physiological responses. The unexpected condition led to substantially more self-reported distress and panic attacks. The experimental conditions did not elicit different autonomic reactions, but those who panicked showed stronger physiological responses than those who did not panic. The findings are consistent with a cognitive model of nocturnal panic attacks.     

A hyperventilation interpretation of the termination of panic attacks: a reply to van den Hout, de Jong, Zandbergen and Merckelbach.

This paper summarizes the brief publication history of how a hyperventilatory positive-feed-back-loop theory of panic attacks explains the termination of panic attacks. A cautionary note is suggested when interpreting generalizations pertaining to panic attacks in panic-disorder sufferers in the everyday world made from laboratory findings based on healthy asymptomatic subjects.