Automatic Negative Evaluation of Suffocation Sensations in Individuals With Suffocation Fear

When dyspnea gets worse: Suffocation fear and the dynamics of defensive respiratory responses to increasing interoceptive threat

In patients with anxiety and/or respiratory diseases, body sensations, particularly from the respiratory system, may increase in intensity and aversiveness and thus lead into defensive action (e.g., escape) or panic. The processes, however, that might contribute to the culmination of symptoms and the switch into defensive action have not been well understood yet. The current study aimed at evaluating an experimental paradigm to characterize the dynamics of defensive mobilization to body sensations increasing in intensity and aversiveness. Persons reporting low and high suffocation fear (SF; N = 69) were exposed to increasingly unpleasant feelings of dyspnea induced by inspiratory resistive loads and a breathing occlusion requiring voluntary breath holding. Respiratory responses were assessed along with subjective reports of anxiety and panic symptoms. Presentation of respiratory loads with increasing physical resistance led to increasingly unpleasant feelings of dyspnea. Twenty-eight participants terminated the exposure prematurely at least once. When dyspnea was severe, high compared to low SF persons exhibited an increased respiratory rate that was accompanied by reports of more intense panic symptoms. Premature terminations of exposure were preceded by a surge in anxiety, breathing frequency, and mouth pressure, and a decrease in tidal volume. We successfully established an experimental paradigm to assess changes in defensive responding with increasing intensity of an interoceptive threat. The current data foster our understanding of behavioral expression patterns observed in patients with anxiety and/or respiratory diseases and the processes involved in the culmination of bodily sensations and anxiety into panic.

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.

Hyperventilation in panic disorder and asthma: empirical evidence and clinical strategies

Sustained or spontaneous hyperventilation has been associated with a variety of physical symptoms and has been linked to a number of organic illnesses and mental disorders. Theories of panic disorder hold that hyperventilation either produces feared symptoms of hypocapnia or protects against feared suffocation symptoms of hypercapnia. Although the evidence for both theories is inconclusive, findings from observational, experimental, and therapeutic studies suggest an important role of low carbon dioxide (CO2) levels in this disorder. Similarly, hypocapnia and associated hyperpnia are linked to bronchoconstriction, symptom exacerbation, and lower quality of life in patients with asthma. Raising CO2 levels by means of therapeutic capnometry has proven beneficial effects in both disorders, and the reversing of hyperventilation has emerged as a potent mediator for reductions in panic symptom severity and treatment success.