Hyperventilation and lactate infusion in the production of panic attacks

Blood, Breath, Fears Redux, and Panic Attacks: Comment on Roth, Wilhelm, and Pettit (2005)

This article discusses the hyperventilation theory (HVT) of panic attacks (PAs) proposed by R. Ley in the context of criticisms raised by W. T. Roth, F. H. Wilhelm, and D. Pettit. Their interpretation of HVT is flawed by misunderstanding, misinterpretation, and oversimplification of the complex psychophysiological principles on which current HVT is based. Consequently, the "propositions" they derive are inappropriate. Further, Roth et al. disregarded/overlooked: (a) differences among types of PAs, (b) abundant empirical evidence that PA patients are distinguished by presence or absence of prominent respiratory symptoms (e.g., overbreathing), and (c) Ley's (1992b) classification of PAs based on 10 psychophysiological distinctions. The review by Roth et al. falls short of standards required to falsify HVT. Current HVT of PAs is tenable and testable.

CO(2) hypersensitivity in recently abstinent alcohol dependent individuals:; A possible mechanism underlying the high risk for anxiety disorder among alcoholics

Alcohol, administered acutely, is known to cause CO(2) hyposensitivity. CO(2) hypersensitivity associated with anxiogenic hyperventilation (HV) could reasonably be expected to emerge as an opponent process upon withdrawal from chronic alcohol use. To test this hypothesis, we applied two well-known methods to quantify CO(2) sensitivity in recently detoxified alcohol-dependent individuals and never alcohol-disordered individuals who are social drinkers. We found that the alcoholic group exhibited significantly greater CO(2) sensitivity than did controls in response to both challenges. Indirect evidence of chronic HV was also obtained. These findings implicate the effect of chronic alcohol use on CNS-based CO(2) sensitivity in heightening the vulnerability to disturbing anxiety symptoms and syndromes exhibited by alcoholic individuals. Future work must verify that pathological drinking actually causes the dysregulated respiratory responding observed in this study as is inferred in our conclusions.

Respiratory and cognitive subtypes of panic. Preliminary validation of Ley's model

A review of the panic disorder literature strongly suggests subtypes of panic attacks, including a respiratory subtype. This study empirically tested several aspects of Ley's panic subtype theory, measuring end-tidal carbon dioxide (ETCO2) levels at baseline, during psychologic and respiratory stressors, and at recovery. As predicted, Type 1 (classic or respiratory) panickers had significantly lower resting ETCO2 compared to Type 3 (cognitive) and to controls. Type 3 panickers did not differ from controls. Physiologic findings support the existence of respiratory and other subtypes of panic attacks in panic disorder. More complex measures of respiration and other physiology are likely required to elicit full subtype profiles. Distinguishing between chronic (compensated) hyperventilators and acute hyperventilators will likely be useful in clarifying the subtypes. Recognizing the need for differential diagnosis of panic attacks can facilitate developing more specific treatment plans and interventions (e.g., restoration of normal ETCO2 in Type 1), improving treatment success rates.

The modification of breathing behavior. Pavlovian and operant control in emotion and cognition

The purpose of this article is to bring attention to breathing as a behavior that can be modified by means of Pavlovian and operant principles of control. With this aim in mind, this paper (a) reviews a selection of early and recent conditioning studies (Pavlovian and operant paradigms) in respiratory psychophysiology, (b) discusses the bidirectional relationship between breathing and emotion/cognition, and (c) discusses theoretical and applied implications that point to new directions for research in the laboratory and clinic. Emphasis is placed on dyspnea/suffocation fear and the acquisition of anticipatory dyspnea/suffocation fear in panic, anxiety, and stress disorders and their concomitant cognitive deficits. Discussions throughout the article focus on research relevant to theory and application, especially applications in programs of remedial breathing (breathing retraining) designed for the treatment of psychophysiological disorders (e.g., panic, anxiety, and stress) and the accompanying cognitive deficits that result from cerebral hypoxia induced by conditioned hyperventilation.

Hyperventilation and panic attacks in general hospital patients

The 2-week prevalence of panic attacks according to DSM-III-R criteria was assessed in 102 general hospital patients with unexplained somatic symptoms suggestive of the hyperventilation syndrome (HVS). Thirty-six patients were classified as panickers. In comparison to nonpanickers, panickers reported more severe panic and hyperventilation symptoms and state anxiety during anxiety episodes in daily life and also obtained higher scores on measures for depression, generalized anxiety, agoraphobic anxiety, and agoraphobic avoidance. During the Hyperventilation Provocation Test, panickers reported more panic and hyperventilation symptoms and state anxiety and also rated their symptoms to be more similar to those occurring in daily life than nonpanickers. However, no differences were observed between panickers and nonpanickers in base excess values or in minute respiratory volume, respiratory rate, or fraction of end-tidal carbon dioxide during the resting, hyperventilation, and recovery phase. It is concluded that the prevalence of panic attacks in this group of patients is relatively high and that medical specialists must be more attentive to the occurrence of panic attacks or panic disorder in general hospital patients with unexplained somatic symptoms suggestive of HVS.

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.

The many faces of Pan: psychological and physiological differences among three types of panic attacks

The thesis of this paper is that failure to recognize the psychological and physiological differences among panic attacks within DSM-IIIR precludes meaningful comparisons and evaluations of research findings, confounds theoretical issues, and impairs the development of more specific, and thereby more effective, programs of treatment. To remedy this, a recommendation is made to define panic attacks on the basis of psychological and physiological distinctions that fit three categories of severity: Type I (classic panic attack), Type II (anticipatory panic attack), and Type III (cognitive panic attack). The logical-empirical rationale for the categories recommended is presented in the context of relevant research findings. Implications for theory, experimental design, and treatment are discussed.

A review of the psychopharmacology of panic disorder: individual differences and non specific factors

This paper critically examines the pharmacological provocation and treatment of panic disorder. An analysis of research findings on how panic attacks are induced indicates that there are psychological and non specific factors that may mediate biochemical etiological models, and these individual differences need to be investigated further. This has important implications for the psychopharmacological management of panic. A review of studies on treating panic disorder with imipramine and alprazolam emphasizes the importance of several non specific factors that include the role of self-directed in vivo exposure and changes in dysphoria and self-efficacy (subjective beliefs regarding personal competency) in predicting outcome. It is recommended that any treatment of panic-related disorders include self-directed, in vivo exposure.

Panic attacks during relaxation and relaxation-induced anxiety: a hyperventilation interpretation

This paper explains how a hyperventilation theory of panic disorder accounts for panic attacks during relaxation and relaxation-induced anxiety. The explanation is based on the observation that chronic hyperventilators maintain a steady state of low pCO2 (arterial carbon dioxide tension) and are, therefore, sensitive to relatively small increases in ventilation when metabolism is low and to relatively sudden reductions in metabolism when ventilation is relatively constant. Thus, if minute volume of air breathed remains constant while the metabolic production of CO2 decreases, as in the case of one who sits down or lies down to relax, respiratory hypocapnea may increase in intensity until it produces the familiar sensations which mark the panic attack. Data from relevant studies of panic attacks during relaxation support the hyperventilation interpretation.

Panic disorder and agoraphobia: fear of fear or fear of the symptoms produced by hyperventilation?

Two versions of the fear-of-fear hypothesis of panic disorder are discussed. The fear-of-the-somatic-effects-of-fear version, which is distinguished from the classical conditioning version, is compared with the hyperventilation theory of panic disorder and agoraphobia. The fear-of-the-somatic-effects-of-fear hypothesis is criticized on the basis of its inability to explain adequately (a) the initiation of panic attacks, (b) the growth in intensity of panic attacks, and (c) the termination of panic attacks. The tenability of the hyperventilation theory is supported by evidence from programs of treatment derived from the basic assumptions of the theory.