Respiratory symptoms and panic in the National Comorbidity Survey: a test of Klein's suffocation false alarm theory

According to suffocation false alarm theory (Arch. Gen. Psychiatry 50 (1993) 31), respiratory symptoms are the symptoms that best distinguish the panic attacks of individuals with panic disorder (PD) from those of individuals without PD. Using National Comorbidity Survey data from those 609 respondents who had lifetime histories of panic attacks or PD, we tested this prediction. Neither respiratory symptom (smothering; dyspnea) strongly differentiated between respondents with PD and those with only panic attacks. Respiratory symptom endorsement was unrelated to PD when the number of other symptoms endorsed was controlled; furthermore, respiratory symptoms had slight effect sizes and were not included in a multivariate context. In contrast, fear of dying had the largest effect size, an association with PD that persisted after control for other symptom endorsement, and a continuing importance in multivariate analyses. Strikingly, panic attack respondents who reported having had only one panic attack were as likely as PD respondents to report respiratory symptoms during panic. These findings, although based on retrospective self-report and thus subject to recall bias, are inconsistent with the hypothesis that respiratory symptoms during panic have diagnostic significance.     

Avoidant coping in panic disorder: a yohimbine biological challenge study

Few studies have addressed whether the use of avoidance-oriented coping strategies is related to the development of panic in patients with panic disorder(PD). Self-report, clinician-rated, and physiological data were collected from 42 individuals who participated in a yohimbine biological challenge study, performed under double-blind, placebo-controlled conditions. Participants included 20 healthy controls and 22 currently symptomatic patients who met DSM-IV-TR diagnostic criteria for PD. Consistent with prediction, patients with PD who had higher perceived efficacy of avoidance-oriented strategies in reducing anxiety-related thoughts reported increased severity in panic symptoms during the yohimbine challenge condition as compared to the placebo. Further, patients with PD who had more fear of cognitive dyscontrol, cardiovascular symptoms, and publicly observable anxiety also reported increased severity in panic symptoms during the challenge. Healthy controls who had more fear of cardiovascular symptoms similarly reported increased severity in panic symptoms during the challenge. No effects were found for heart rate response to the challenge agent. These results provide support for the role of avoidance-oriented coping strategies and fear of anxiety-related symptoms as risk and maintenance factors in the development of panic symptoms, particularly within a biological challenge model.     

Avoidant coping in panic disorder: a yohimbine biological challenge study

Abstract

Few studies have addressed whether the use of avoidance-oriented coping strategies is related to the development of panic in patients with panic disorder(PD). Self-report, clinician-rated, and physiological data were collected from 42 individuals who participated in a yohimbine biological challenge study, performed under double-blind, placebo-controlled conditions. Participants included 20 healthy controls and 22 currently symptomatic patients who met DSM-IV-TR diagnostic criteria for PD. Consistent with prediction, patients with PD who had higher perceived efficacy of avoidance-oriented strategies in reducing anxiety-related thoughts reported increased severity in panic symptoms during the yohimbine challenge condition as compared to the placebo. Further, patients with PD who had more fear of cognitive dyscontrol, cardiovascular symptoms, and publicly observable anxiety also reported increased severity in panic symptoms during the challenge. Healthy controls who had more fear of cardiovascular symptoms similarly reported increased severity in panic symptoms during the challenge. No effects were found for heart rate response to the challenge agent. These results provide support for the role of avoidance-oriented coping strategies and fear of anxiety-related symptoms as risk and maintenance factors in the development of panic symptoms, particularly within a biological challenge model.     

Sex differences in response to a panicogenic challenge procedure: an experimental evaluation of panic vulnerability in a non-clinical sample

Epidemiological studies show that women are twice as likely as men to develop panic disorder (PD) during their lifetimes. Data from retrospective studies also suggest that women are more distressed by panic and other negative emotional states than men, and that this tendency may precede the development of PD. The present prospective study sought to expand this work by evaluating sex differences in the predisposition to panic in individuals without PD or other forms of psychopathology. Participants (N=96; 52 women) were exposed to 12 panicogenic inhalations of 20% CO2-enriched air while physiological (e.g., heart rate, electrodermal response, Frontalis EMG) and self-report (e.g., subject distress, fear, frequency and severity of DSM-IV panic symptoms) response domains were monitored. As expected, magnitude of autonomic responding failed to reliably discriminate between women and men. Yet, women reported more fear and panic immediately following the challenge procedure relative to men, and this sex difference persisted when assessed again 30 min post-challenge. Implications of these results are discussed broadly in the context of biopsychosocial accounts of sex differences in the clinical presentation of PD.     

Does coping predict CO2-induced panic in patients with panic disorder?

Patients with panic disorder (PD) show maladaptive coping but the role of coping in the pathogenesis of panic is unclear. This study examined general coping and panic-specific coping as predictors of fear responding to CO2 inhalation. Subjective and physiological responses including panic attacks were assessed in 45 patients with PD and 45 matched nonclinical controls. Measures of coping were the primary predictors used in the analyses. Consistent with other reports, patients with PD reported increased emotion-focused coping and there was an association between emotion-focused coping and subjective reactivity. However, only panic-specific coping predicted panic attacks in response to the CO2 challenge.     

Response patterns to repeated CO2 inhalation in individuals with high anxiety sensitivity.

The present report extends previous work which has documented two distinct response patterns to repeated presentation of interoceptive cues (using CO2 inhalation) in PD patients [Beck, J. G. & Shipherd, J. C. (1997). Repeated exposure to interoceptive cues: does habituation of fear occur in panic disorder patients? Behaviour Research and Therapy, 35, 551-557]. We were interested in determining if these two patterns of fear habituation and sensitization would be noted in panic-naive individuals who reported high levels of Anxiety Sensitivity. A second aspect of this report examined whether attention to bodily sensations versus to neutral material would impact fear habituation and sensitization. Participants included 43 panic-naive individuals who scored at least 1 standard deviation above norms on the Anxiety Sensitivity Index. Results indicated that 37% of the sample reported habituation of fear, 47% reported fear sensitization and 16% demonstrated relatively stable fear levels across 12 inhalations of CO2 during session 1. The attentional manipulation did not exert a pronounced influence on anxiety, panic symptom severity, skin conductance, or heart rate in either Habituators or Sensitizers during session 2. These results are discussed in light of their relevance in understanding fundamental psychopathological processes underlying Panic Disorder.     

Differences in reported symptom profile between panic disorder and other DSM-III-R anxiety disorders.

Previous research has indicated that reports of panic attacks are associated with a different set of symptoms to reports of generalized anxiety. The present two studies attempted to extend these findings to specific (situational) fears. In Study 1, 55 subjects with panic disorder were compared on their symptom profile during their panic attacks to 65 subjects with other anxiety disorders [simple phobia, social phobia and obsessive-compulsive disorder (OCD)] during response to their feared cue. The results indicated that, compared to subjects with other anxiety disorders, subjects with panic disorder were more likely to report parasthesias, dizziness, faintness, unreality, dyspnea, fear of dying and fear of going crazy/losing control. In Study 2, 90 subjects meeting diagnostic criteria for both panic disorder and another anxiety disorder (simple phobia, social phobia or OCD) were compared on the symptoms experienced during their unexpected panic attacks and their situationally-triggered fears respectively. Combining the symptoms found in Study 1 to differ between the groups into a linear combination, there was a significant interaction found between the type of fear reaction (panic attack vs cued fear response) and symptom group. Taken together, these findings suggest that reports of unexpected panic attacks associated with panic disorder are characterized by a different symptom profile to reports of specific fear reactions that are part of a phobic disorder or OCD.     

Mechanisms of change in cognitive behavioral therapy for panic disorder: The unique effects of self-efficacy and anxiety sensitivity

The present study examined temporal dependencies of change of panic symptoms and two promising mechanisms of change (self-efficacy and anxiety sensitivity) during an 11-session course of cognitive-behavior therapy (CBT) for Panic Disorder (PD). 361 individuals with a principal diagnosis of PD completed measures of self-efficacy, anxiety sensitivity, and PD symptoms at each session during treatment. Effect size analyses indicated that the greatest changes in anxiety sensitivity occurred early in treatment, whereas the greatest changes in self-efficacy occurred later in treatment. Results of parallel process latent growth curve models indicated that changes in self-efficacy and anxiety sensitivity across treatment uniquely predicted changes in PD symptoms. Bivariate and multivariate latent difference score models indicated, as expected, that changes in anxiety sensitivity and self-efficacy temporally preceded changes in panic symptoms, and that intraindividual changes in anxiety sensitivity and self-efficacy independently predicted subsequent intraindividual changes in panic symptoms. These results provide strong evidence that changes in self-efficacy and anxiety sensitivity during CBT influence subsequent changes in panic symptoms, and that self-efficacy and anxiety sensitivity may therefore be two distinct mechanisms of change of CBT for PD that have their greatest impact at different stages of treatment.     

Book Reviews

Panic attacks and depression frequently co‐occur, and the presence of this co‐morbidity is often associated with worse outcomes compared with each disorder alone. Despite this, not everyone who experiences panic attacks also suffers from depression, suggesting that individual difference factors may play a role in this co‐morbidity. The purpose of this study was to provide a preliminary investigation of two such individual difference factors, examining the role of anxiety sensitivity and lack of emotional approach coping in depressive symptom severity among a non‐clinical sample of uncued panickers. A sample of 79 college students reporting the occurrence of uncued panic attacks within the past year completed a series of questionnaires assessing the lower‐order factors of anxiety sensitivity, emotional approach coping, panic attack frequency, panic‐related disability, panic symptom severity and depressive symptom severity. Participants with more severe depressive symptoms reported greater anxiety sensitivity, panic attack frequency, panic symptom severity, panic‐related disability and lack of emotional approach coping. The particular anxiety sensitivity dimension of fear of cognitive dyscontrol and lack of emotional approach coping emerged as the best predictors of depressive symptom severity. Findings are discussed in terms of their implications for the improved understanding of this co‐morbidity, as well as its treatment.     

The role of anxiety sensitivity and lack of emotional approach coping in depressive symptom severity among a non-clinical sample of uncued panickers

Panic attacks and depression frequently co-occur, and the presence of this co-morbidity is often associated with worse outcomes compared with each disorder alone. Despite this, not everyone who experiences panic attacks also suffers from depression, suggesting that individual difference factors may play a role in this co-morbidity. The purpose of this study was to provide a preliminary investigation of two such individual difference factors, examining the role of anxiety sensitivity and lack of emotional approach coping in depressive symptom severity among a non-clinical sample of uncued panickers. A sample of 79 college students reporting the occurrence of uncued panic attacks within the past year completed a series of questionnaires assessing the lower-order factors of anxiety sensitivity, emotional approach coping, panic attack frequency, panic-related disability, panic symptom severity and depressive symptom severity. Participants with more severe depressive symptoms reported greater anxiety sensitivity, panic attack frequency, panic symptom severity, panic-related disability and lack of emotional approach coping. The particular anxiety sensitivity dimension of fear of cognitive dyscontrol and lack of emotional approach coping emerged as the best predictors of depressive symptom severity. Findings are discussed in terms of their implications for the improved understanding of this co-morbidity, as well as its treatment.     

A Review of Cognitive Behavioral Therapy for Panic Disorder in Patients with Chronic Obstructive Pulmonary Disease: The Rationale for Interoceptive Exposure

Panic disorder commonly co-occurs in patients with chronic obstructive pulmonary disease (COPD), and translational interventions are needed to address the fear of physiological arousal in this population. This paper examines the utility of interoceptive exposures (IE), a key component of cognitive behavioral therapy (CBT) for panic disorder, in patients with comorbid panic and COPD. Our translational review of the literature suggests that IE is supported by both cognitive- and learning-theory perspectives of panic, and that the breathing exercises associated with IE are safe and highly compatible with existing pulmonary rehabilitation exercises for COPD. Unfortunately, few research studies have examined the use of CBT to treat anxiety in COPD patients, and none have included IE. Given the strong theoretical and empirical support for the use of IE, we suggest that mental health providers should consider incorporating IE into CBT interventions for patients with comorbid panic and COPD.     

A Study of Panic Attacks in University Students of Iran

This study examined the parameters of panic, fear, and avoidance among university students in Iran. Data were collected from 347 students using Farsi translations of the Panic Attack Questionnaire, Beck Depression Inventory, Taylor Manifest Anxiety Scale, State-Trait Anxiety Inventory, and Anxiety Sensitivity Index. Thirty-eight percent of participants reported panic attacks in the past year and 21.4% reported panic attacks in the past 4 weeks when prompted by a broad definition of panic. Men and those with unexpected panic reported greater panic severity whereas women with panic attacks reported greater situational fear and avoidance. Panickers who satisfied DSM-III-R panic disorder (PD) criteria reported greater lifestyle restriction and general psychopathology. The findings provide tentative support for cross-cultural similarity in panic phenomenology and the validity of DSM-III-R PD criteria among university students in Iran. The results are discussed by reference to nonclinical panic research and general themes of Iranian culture.     

Predictors of Self-Reported Anxiety and Panic Symptoms: An Evaluation of Anxiety Sensitivity, Suffocation Fear, Heart-Focused Anxiety, and Breath-Holding Duration

The purpose of this study was to examine the extent to which anxiety-related individual difference variables predict anxious responding when individuals experience aversive bodily sensations. Thus, we explore several psychological and behavioral predictors of response to a single 25-sec inhalation of 20% carbon dioxide-enriched air in 70 nonclinical participants. Predictor variables included anxiety sensitivity, suffocation fear, heart-focused anxiety, and breath-holding duration. Multiple regression analyses indicated that only anxiety sensitivity significantly predicted postchallenge panic symptoms, whereas both anxiety sensitivity and suffocation fear predicted postchallenge anxiety. These data are in accord with current models of panic disorder that emphasize the role of fear of fear in producing heightened anxiety and panic symptoms and help clarify specific predictors of anxiety-related responding to biological challenge.     

Symptom Attributions Across the Menstrual Cycle in Women with Panic Disorder

Women with panic disorder are likely to experience greater menstrual-specific symptoms (e.g., headaches, cramps) as well as more panic/anxiety-related symptoms (e.g., dizziness, faintness, chest pain, heart pounding), and may be more likely to experience these symptoms during the premenstrual phase. This study examines the attributions women make about the somatic and affective symptoms they experience during the menstrual cycle. Using a 30-day prospective design, women with and without panic disorder monitored physical and affective symptoms. Participants reported on severity of various symptoms and a primary cause for each symptom (menstrual cycle-related, panic/anxiety related, stress-related, health-related). Women with panic disorder reported more panic attacks during the premenstrual phase compared to other cycle phases. They also reported more severe affective and panic symptoms during the premenstrual phase compared to other phases, but did not significantly differ from the comparison group in menstrual symptom severity across the three cycle phases. Although women with panic disorder attributed more panic/anxiety-related causes for their symptoms across the menstrual cycle, they were able to discriminate between panic/anxiety causes and menstrual cycle-related causes. Women with panic disorder may benefit for therapy that focuses on their exacerbation of panic symptoms during the premenstrual phase.     

Impaired discriminative fear-conditioning resulting from elevated fear responding to learned safety cues among individuals with panic disorder

Classical fear-conditioning is central to many etiologic accounts of panic disorder (PD), but few lab-based conditioning studies in PD have been conducted. One conditioning perspective proposes associative-learning deficits characterized by deficient safety learning among PD patients. The current study of PD assesses acquisition and retention of discriminative aversive conditioning using a fear-potentiated startle paradigm. This paradigm was chosen for its specific capacity to independently assess safety- and danger learning in the service of characterizing putative anomalies in each type of learning among those with PD. Though no group difference in fear-potentiated startle was found at retention, acquisition results demonstrate impaired discriminative learning among PD patients as indexed by measures of conditioned startle-potentiation to learned safety and danger cues. Importantly, this discrimination deficit was driven by enhanced startle-potentiation to the learned safety cue rather than aberrant reactivity to the danger cue. Consistent with this finding, PD patients relative to healthy individuals reported higher expectancies of dangerous outcomes in the presence of the safety cue, but equal danger expectancies during exposure to the danger cue. Such results link PD to impaired discrimination learning, reflecting elevated fear responding to learned safety cues.     

Intolerance of Uncertainty as a Contributor to Fear and Avoidance Symptoms of Panic Attacks

Panic disorder symptoms are persistent for 50–80% of cases even after treatment, resulting in experiences of disability and dissatisfaction in life. Previous research has focused on anxiety sensitivity (AS) and its dimensions as contributing to symptoms of panic disorder; however, recent research has suggested that intolerance of uncertainty (IU)—the tendency for a person to consider the possibility of a negative event occurring as threatening, irrespective of the actual probability of its occurrence—may also play a critical role. The current study was designed to assess the specific relationships between dimensions of IU (i.e. prospective IU and inhibitory IU) and the fear and avoidance symptoms associated with panic disorder. Participants included 122 community members (81% women) with a history of at least one panic attack who participated in a larger study on fear. Participants completed measures of AS, IU, and panic disorder symptoms. Correlation and regression analyses supported a significant and substantial relationship between AS, inhibitory IU, and panic disorder symptoms. Inhibitory IU accounted for relatively more variance in avoidance symptoms related to panic disorder than did the fears of physical sensations dimension of AS. As such, further investigation of the role of IU in panic disorder symptoms appears warranted. Comprehensive results, implications, and directions for future research are discussed.     

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.     

Symptoms of Specific and Generalized Social Phobia: An Examination of Discriminant Validity and Structural Relations With Mood and Anxiety Symptoms

Current models divide social phobia into specific (SSP) and generalized (GSP) subtypes and suggest strong overlap between GSP and avoidant personality disorder (APD). Meanwhile, other research suggests reclassifying anxiety and mood disorders as fear and distress disorders. To unify these separate lines of research, this study was designed to test the hypothesis that SSP is more related to fear disorders (e.g., panic and phobias), whereas GSP and APD are more related to distress disorders (e.g., depression and generalized anxiety). Confirmatory factor analysis suggested the best-fitting model had symptoms of GSP, APD, and depression loading on one factor, and symptoms of SSP, panic, and specific phobias loading on a second factor. Key components of this model were (a) the inclusion of GAD symptoms reduced model fit and (b) GSP and APD symptoms significantly predicted SSP symptoms; this is consistent with conceptualizations of individuals with both GSP and SSP reporting performance anxiety.     

Habituation or Normalization? Experiential and Respiratory Recovery From Voluntary Hyperventilation in Treated Versus Untreated Patients With Panic Disorder

Psychophysiological theories postulate respiratory dysregulation as a mechanism contributing to panic disorder (PD). Additionally, symptomatic and respiratory recovery from voluntary hyperventilation (HVT-recovery) have been shown to lag in PD and it is unclear if HVT-recovery normalizes with treatment. Thirty-seven panic disorder patients were randomized to hypoventilation therapy (TX, n = 20) or waitlist control (WL, n = 17) (Meuret et al., 2008). In a secondary analysis, their HVT-recovery was analyzed at pre- and post-TX/WL, compared to 29 healthy controls (HC). HVT included three phases: 5-min baseline, 3-min hyperventilation, and 8-min recovery. HVT-elicited symptom severity and anxiety were rated following each phase, and end-tidal PCO₂ and respiratory rate (RR) were recorded throughout. Treatment, compared to WL, was highly effective in reducing PD pathology (d = 2.21, Meuret et al., 2008). At pre-TX/WL, PD demonstrated delayed HVT-recovery PCO₂ and higher RR. Treated patients demonstrated normalization of HVT-recovery for PCO₂ and RR; however, improvements of HVT-recovery for symptom severity and anxiety did not differ between TX and WL. Results replicate pretreatment HVT respiratory recovery abnormalities in PD and further demonstrate normalization, comparable to HC, following successful treatment. The results provide support for respiratory dysregulation as a feature of PD and demonstrate the utility of HVT respiratory recovery as treatment outcome measure for respiration-based PD therapy.     

Relations Among Symptoms of Social Phobia Subtypes, Avoidant Personality Disorder, Panic, and Depression

This study's primary goal was to examine relations between symptoms of specific social phobia (SSP), generalized social phobia (GSP), avoidant personality disorder (APD), and panic and depression. Past research has suggested a single social phobia continuum in which SSP displays less symptom severity than GSP or APD. We found SSP symptoms correlated less strongly with depression but more strongly with panic relative to both GSP and APD symptoms. These findings challenge a unidimensional model of social phobia, suggesting a multidimensional model may be more appropriate. These findings also inform current research aimed at classifying mood and anxiety disorders more broadly by identifying that the different factors of fear versus distress appear to underlie different subtypes of social phobia.