Detection of somatic sensations in panic disorder

Psychophysiological responses to CO₂inhalation

Inhalation of CO(2)-enriched air has been used as a laboratory model for a number of anxiety disorders, such as general anxiety disorder and panic disorder. Because studies describing psychophysiological responses to this challenge are scarce, the present studies investigated skin conductance level, eyeblink startle, self-reported anxiety and fractional end-tidal carbon dioxide during inhalation of CO(2)-enriched air. In study 1, thirty-five healthy volunteers inhaled 7.5% CO(2) for 2min. In study 2, twenty healthy volunteers inhaled 20% CO(2) for 30s. Control groups (N=20 in each study) inhaled room air during the same time periods. Compared to room air breathing, both CO(2)-mixtures were associated with increases in skin conductance levels, self-reported anxiety and fractional end-tidal CO(2.) Eyeblink startles were inhibited during CO(2) compared to room air breathing in both experiments. Our findings suggest that inhalation of CO(2)-enriched air is associated with a circa-strike defensive response pattern, corroborating its application as an interoceptive, panic-relevant stimulus in fear research.

Increased interoceptive awareness in fear of flying: sensitivity to suffocation signals

In flight phobia, particular environmental factors can facilitate a fear response. The current study aimed to explore the relationship between respiratory sensations and fear of flying: individuals with fear of flying may be more sensitive to suffocation signals and could experience more bodily sensations as a consequence of an added resistive respiratory load. The sample included 19 subjects with fear of flying and 19 controls. Each subject wore a mask to which a respiratory load could be added. First, an interference paradigm was used: respiratory loads were presented during a tone detection task. Next, subjects were asked to detect the loads. After each task, subjects reported their somatic sensations. All subjects showed interference of the respiratory loads. However, subjects with fear of flying were more accurate in detecting the loads, thereby indicating higher interoceptive awareness. Moreover, their superior accuracy was related to increased bodily sensations: a higher interoceptive awareness resulted in increased symptom reporting. It follows that treatment interventions for fear of flying should be supplemented with interventions that target internal stimuli.

What is an anxiety disorder?

Initiated as part of the ongoing deliberation about the nosological structure of DSM, this review aims to evaluate whether the anxiety disorders share features of responding that define them and make them distinct from depressive disorders, and/or that differentiate fear disorders from anxious-misery disorders. The review covers symptom self-report as well as on-line indices of behavioral, physiological, cognitive, and neural responding in the presence of aversive stimuli. The data indicate that the anxiety disorders share self-reported symptoms of anxiety and fear; heightened anxiety and fear responding to cues that signal threat, cues that signal no threat, cues that formerly signaled threat, and contexts associated with threat; elevated stress reactivity to aversive stimuli; attentional biases to threat-relevant stimuli and threat-based appraisals of ambiguous stimuli; and elevated amygdala responses to threat-relevant stimuli. Some differences exist among anxiety disorders, and between anxiety disorders and depressive disorders. However, the differences are not fully consistent with proposed subdivisions of fear disorders vs. anxious misery disorders, and comparative data in large part are lacking. Given the high rates of co-morbidity, advances in our understanding of the features of responding that are shared across vs. unique to anxiety and depressive disorders will require dimensional approaches. In summary, the extant data help to define the features of responding that are shared across anxiety disorders, but are insufficient to justify revisions to the DSM nosology at this time.

Psychosocial interventions for panic disorder after coronary artery bypass graft: a case study

It is increasingly recognized that patients with cardiovascular disease may also suffer from concurrent psychological problems. Many patients present to emergency services and cardiologists with a history of panic disorder. Because of the similarity of presenting symptoms, these patients are often undiagnosed and consequently have slower recovery times and are costly to the healthcare system. Panic disorder is a significant public health problem; however, it is a treatable condition. Healthcare providers should be aware of its occurrence in cardiovascular disease. This case study describes the use of psychosocial interventions, such as the cognitive behavior therapy, in the management of panic disorder after coronary artery bypass graft. A 64-year-old man was treated with 9 sessions of cognitive behavior therapy over a 5-month period. Baseline assessment showed significant distress and deficit in functioning. Following intervention, there was marked reduction in objective and subjective measurement of distress and overall improvement in functioning. Healthcare providers, particularly nurses, need to consider the integration of psychosocial interventions into areas of critical care to provide effective and holistic care. Preoperative screening would be helpful as well.

Heartbeat sensitivity in adults with congenital heart disease

This study tested the hypothesis that patients with a congenital heart disease are sensitive regarding heartbeat perception, reflected in enhanced attention for heartbeat, estimation of own heart rate, and a vulnerability to become anxious by listening to heartbeat sounds. Twenty adults with a congenital heart disease, and 20 healthy controls conducted 3 experimental tasks: a concentration task during distraction by heartbeat sounds, own heart rate estimation, and exposure to different patterns of heartbeat sounds. The results showed that patients were more distracted by heartbeat, and were also worse at estimating heart rate than controls. However, heartbeat sounds did not evoke anxiety. In conclusion, patients with a congenital heart disease may differ from controls in heartbeat perception, but there was no support for obsessive monitoring for heartbeat or excessive reactions to heartbeat sounds.

An integrated cognitive model of panic disorder: The role of positive and negative cognitions

One reason for the neglect of the role of positive factors in cognitive-behavioural therapy (CBT) may relate to a failure to develop cognitive models that integrate positive and negative cognitions. Bandura [Psychol. Rev. 84 (1977) 191; Anxiety Res. 1 (1988) 77] proposed that self-efficacy beliefs mediate a range of emotional and behavioural outcomes. However, in panic disorder, cognitively based research to date has largely focused on catastrophic misinterpretation of bodily sensations. Although a number of studies support each of the predictions associated with the account of panic disorder that is based on the role of negative cognitions, a review of the literature indicated that a cognitively based explanation of the disorder may be considerably strengthened by inclusion of positive cognitions that emphasize control or coping. Evidence to support an Integrated Cognitive Model (ICM) of panic disorder was examined and the theoretical implications of this model were discussed in terms of both schema change and compensatory skills accounts of change processes in CBT.

Heartbeat awareness and heart rate reactivity in anxiety sensitivity: a further investigation

We examined the effects of anxiety sensitivity (AS) and arousal induction on heartbeat awareness and heart rate reactivity in a nonclinical undergraduate sample. Students were randomly selected from a larger screening sample to fill two groups (high and low AS; n = 15 per group) based on Anxiety Sensitivity Index (ASI) [Peterson, R. A., & Reiss, S. (1992). Anxiety Sensitivity Index manual (2nd ed. revised). Worthington, OH: International Diagnostic Systems] scores. Participants completed a mental arithmetic/spelling task to induce arousal. At two phases (i.e., baseline vs. stress), participants estimated their heart rates during specified intervals using a mental tracking paradigm. Actual heart rates were simultaneously measured. Although heart rate did increase significantly from baseline to stress phases, high and low AS groups did not differ in terms of heart rate reactivity to the stressor. As hypothesized, high AS individuals were more accurate in estimating their actual heart rate as compared to low AS individuals. Contrary to hypothesis, the AS group differences in accuracy of heartbeat estimations did not vary across baseline vs. stress phases. Interestingly, only low AS individuals provided heart rate estimates which were significantly lower than their actual heart rate readings. Although high and low AS individuals did not differ in actual heart rate, high AS individuals provided significantly higher heart rate estimates than low AS individuals. These results are consistent with the interoceptive sensitivity hypothesis. Implications of the greater heartbeat awareness of high AS individuals are discussed.

Reactivity to interoceptive cues in nocturnal panic

In this study, patients with panic disorder (PD) who suffered nocturnal panic (NP) attacks were compared with PD patients who never experienced NP attacks and healthy controls. Three tasks were chosen to evaluate attention to cardiac cues, reactivity to induction of respiratory cues, and reactivity to relaxation cues. Relative to healthy controls, PD groups reported more fear of all three tasks and showed more physiological arousal in response to the hyperventilation task. The only task on which the two PD groups differed was the relaxation task, where nocturnal panickers were significantly more distressed. These findings are consistent with the notion that nocturnal panickers are fearful of states involving a diminution of conscious awareness or vigilance.

A review of psychological factors/processes affecting anxious responding during voluntary hyperventilation and inhalations of carbon dioxide-enriched air

Despite advances in our understanding of the nature of anxiety-related responding during periods of elevated bodily arousal, it is not necessarily evident by what psychological mechanisms anxiety is produced and maintained. To address this issue, researchers have increasingly employed biological challenge procedures to examine how psychological factors affect anxious responding during elevated bodily arousal. Of the challenging procedures, hyperventilation and inhalations of carbon dioxide-enriched air have been among the most frequently employed, and a relatively large body of literature using these procedures has now accumulated. Unfortunately, existing reviews do not comprehensively examine findings from hyperventilation and inhalations of carbon dioxide studies, and only rarely the methodological issues specific to these studies. To address these issues, we review the voluntary hyperventilation and carbon dioxide-enriched air literature in order to identify the primary methodological issues/limitations of this research and address the extent to which psychological variables influence anxious responding to such challenges. Overall, we conclude challenge research is a promising paradigm to examine the influence of psychological variables in anxious responding, and that such work will likely be enhanced with greater attention to psychological process issues.

Attention to bodily sensations: a test of the cognitive-attentional model of panic

This paper describes a study designed to test the cognitive-attentional model of panic. This model suggests that attention to internal sensations is likely to increase misinterpretation of them as representing a serious threat to health, which in turn might increase anxiety. In the present study, instructions for internal attentional focus were predicted to increase symptom reporting, anxiety, and catastrophic symptom attributions. Two groups, patients diagnosed with panic disorder with agoraphobia (PDA) and normal controls, watched a stressful film; half of each group was asked to attend to their internal sensations while watching, and the other half to focus on the film. In the normal controls, the manipulation was effective in modifying attentional focus, and the self-focused attention group became more anxious, reported more symptoms, and made more negative symptom attributions. However, in the PDA group, attentional focus was high in both conditions, and perhaps for this reason the intervention had no effect on mood, symptoms, catastrophic cognitions, or symptom attribution.

Attention, arousal and expectancies in anxiety and sexual disorders

This paper reviews experimental studies of sexual disorders and anxiety disorders. Studies were mainly carried out in the laboratories and clinics with which each of the two authors is associated. Sex and anxiety are rather antipodal emotions but contrary to traditional views, there is no reason to believe that anxiety disorders are driven by underlying sexual problems or that sexual problems are maintained by anxiety. Both sex research and anxiety research focused on selective processing of disorder relevant information in patients. More in particular, studies are clustered in three groups. First, the authors examined selective attention for threat-related material in anxious patients and for non-sex-related material in sexually dysfunctional patients. Second, the (mis)interpretation of response information in both disorders is compared. Finally the authors discuss biased expectancies in anxiety and sexual disorders. Symmetries and asymmetries are highlighted and lines for further research are sketched.

Anxiety sensitivity, state and trait anxiety, and perception of change in sympathetic nervous system arousal

The psychological models of panic disorder predict that persons with this condition may demonstrate enhanced acuity for somatic stimuli, but research to date has produced conflicting results. Most studies have investigated acuity for cardiovascular responses such as heart rate. which may represent an inadequate test of this hypothesis because they would be unlikely to detect persons who respond maximally to panic through other physiological systems. The present study investigated the detection of changes in pulse transit time (PTT), as a reliable and omnibus measure of sympathetic nervous system activity, with 36 healthy volunteers. We found that accurate perception of changes in PTT was consistently related to higher levels of trait anxiety and anxiety sensitivity, both of which are risk factors for the development of anxiety disorders in general. and panic disorder in particular. served.

Catastrophic cognitions in panic disorder with and without agoraphobia

The cognitive models of panic disorder with (PDA) or without (PD) agoraphobia are now widely recognised. These models propose that patients misinterpret external or internal cues in a catastrophic manner and as a result of these catastrophic cognitions the symptoms are maintained. There is now a large body of empirical evidence for this proposal and the aim of this paper is to systematically review the literature to evaluate whether the empirical evidence supports the contribution of catastrophic cognitions to PD and PDA. Empirical studies using different methodologies, such as interview, questionnaire, self-monitoring, and in vivo techniques are reviewed. The results indicate there is substantial empirical evidence in support of the central role of catastrophic cognition in cognitive models. Different methodologies provided convergent support for the importance of catastrophic cognitions in the maintenance of panic disorder and agoraphobia. Limitations in the interpretation of the existing research are highlighted and future research directions are proposed.

No superior perception of hyperventilatory sensations in panic disorder

It has been argued that panic disorder patients may be more skilled at detecting changes in actual physiology than others. The present study investigated if panic patients are better than controls in perceiving sensations produced by light hyperventilation. Twelve panic patients and 28 control subjects underwent a procedure in which they were exposed 12 times to 1 min of light hyperventilation or 1 min of 'placebo' hyperventilation (isocapnia). Differences in sensations reported during real hyperventilation were compared to sensations reported during 'placebo' hyperventilation. Results demonstrated an absence of superior perception of hyperventilatory sensations in panic patients.

The low specificity of the Hyperventilation Provocation Test

The Hyperventilation Provocation Test (HVPT) has become a routine procedure in the diagnosis of hyperventilation syndrome (HVS). During an HVPT the patient voluntarily overbreathes for several minutes to produce hypocapnia. The test is considered positive if the induced symptoms are recognized by the patient as similar to those experienced in daily life. The present study tests the assumption that hypocapnia is the primary trigger for symptoms during an HVPT. In a randomized double-blind crossover design. 115 patients suspected of HVS and 40 healthy controls performed an HVPT and a placebo test (PT, isocapnic overbreathing). The HVPT induced more symptoms than the PT, especially more neuromuscular symptoms, cerebral symptoms, paresthesias, and temperature sensations. However, the absolute difference between the number of symptoms induced by the HVPT and PT was small. In patients, the PT induced 66% of symptoms induced by the HVPT. In the control group this percentage was 60%. The low specificity of the HVPT implies that symptom recognition during the HVPT is invalid as a diagnostic criterion for HVS.