Anxiety sensitivity and history of panic as predictors of response to hyperventilation

The effects of verbal and imaginal worry on panic symptoms during an interoceptive exposure task

Previous research has documented the inhibitory effects of worry on cardiovascular reactivity to subsequently presented fear-relevant stimuli. Although theoretical assertions point to the verbal-linguistic (as opposed to imagery-based) nature of worry as the cause of these inhibitory effects, extant research investigating the effects of worrisome thinking on subsequent anxiety-eliciting tasks has not isolated the verbal-linguistic nature of worry as the active ingredient in its suppressive effects on arousal. Furthermore, prior research has not examined the potential effects of worry on maintenance of panic symptoms. In this study, participants high in anxiety sensitivity were asked to engage in verbal worry, imaginal worry, or relaxation prior to each of three repeated presentations of an interoceptive exposure task. Relaxation was associated with lower initial subjective fear that remained low across repeated exposures, and related stable sympathetic arousal (and decreased heart rate) over time. Imagery-based worry was associated with moderate initial subjective fear that was sustained across repeated exposures, and sympathetic arousal (and heart rate) that was likewise stable over time. However, verbal worry was associated with high initial subjective fear that was sustained over time, but sympathetic arousal (and heart rate) that decreased across repeated exposures. Thus, verbal worry was uniquely associated with a lack of synchronous response systems and maintenance of anxious meaning over time. Theoretical and clinical implications are discussed.

Repeated Interoceptive Exposure in Individuals With High and Low Anxiety Sensitivity

Interoceptive exposure is one component in cognitive behavioral therapy of panic disorder. The present investigation addressed changes in defensive mobilization during repeated interoceptive exposure using a standardized hyperventilation procedure. 26 high and 22 low anxiety sensitive persons (ASI, Peterson & Reiss, 1992) went through two guided hyperventilation and normoventilation procedures, spaced one week apart. Breathing parameters, startle response magnitudes and symptom reports were measured. All participants successfully adhered to the guided breathing procedures. Both groups comparably reported more symptoms during hyperventilation than normoventilation in both sessions. Only high-AS participants displayed potentiated startle magnitudes after the first hyperventilation vs. normoventilation. One week later, when the hyperventilation exercise was repeated, this potentiation was no longer present. Thus, high and low-AS groups no longer differed in their defensive mobilization to symptom provocation. Furthermore, the number of reported baseline symptoms also decreased from session one to session two in the high-AS group. While high-AS reported increased baseline anxiety symptoms in session 1, groups did not differ in session 2. Results indicate a reduction of defensive mobilization during repeated interoceptive exposure.

Heart-Focused Anxiety in Patients With Noncardiac Chest Pain: Structure and Validity

Heart-focused anxiety (HFA) is a fear of cardiac sensations driven by worries of physical health catastrophe. HFA is impairing and distressing and has been shown to disproportionately affect individuals with noncardiac chest pain (NCCP), chest pain that persists in the absence of an identifiable source. The Cardiac Anxiety Questionnaire (CAQ) is a measure designed to assess HFA. The aim of this study was to evaluate the psychometric properties and factor structure of the CAQ in a sample of 229 adults diagnosed with NCCP. Results demonstrated that the CAQ is a useful measure of HFA in patients with NCCP and that a four-factor model including fear of cardiac sensations, avoidance of activities that elicit cardiac sensations, heart-focused attention, and reassurance seeking was the best fit for the data. Additionally, associations between CAQ subscales and two measures of health-related behaviors-pain-related interference and health care utilization-provided evidence of concurrent validity. Treatment implications are also discussed.

The role of menstrual cycle phase and anxiety sensitivity in catastrophic misinterpretation of physical symptoms during a CO(2) challenge

The current study examined the interactive effects of anxiety sensitivity (AS; fear of anxiety and anxiety-related sensations) and menstrual cycle phase (premenstrual phase vs. follicular phase) on panic-relevant responding (i.e., cognitive and physical panic symptoms, subjective anxiety, and skin conductance level). Women completed a baseline session and underwent a 3-min 10 % CO(2)-enriched air biological challenge paradigm during her premenstrual and follicular menstrual cycle phases. Participants were 55 women with no current or past history of panic disorder recruited from the general community (M (age) = 26.18, SD = 8.9) who completed the biological challenge during both the premenstrual and follicular cycle phases. Results revealed that women higher on AS demonstrated increased cognitive panic symptoms in response to the challenge during the premenstrual phase as compared to the follicular phase, and as compared to women lower on AS assessed in either cycle phase. However, the interaction of AS and menstrual cycle phase did not significantly predict physical panic attack symptoms, subjective ratings of anxiety, or skin conductance level in response to the challenge. Results are discussed in the context of premenstrual exacerbations of cognitive, as opposed to physical, panic attack symptoms for high AS women, and the clinical implications of these findings.

Anxiety sensitivity, the menstrual cycle, and panic disorder: a putative neuroendocrine and psychological interaction

The 2:1 female-to-male sex difference in the prevalence of panic disorder (PD) suggests that there is a sex-specific vulnerability involved in the etiology and/or maintenance of this disorder. The purpose of this paper is to present a new conceptual model, which emphasizes the interaction between a cognitive vulnerability for PD, anxiety sensitivity, and the effects of progesterone and its metabolite, allopregnanolone, on behavioral and physiological responses to stress during the premenstrual phase. This interaction is proposed to be a potential sex-specific pathway that may initiate and/or maintain panic and anxiety symptoms in women. This review paper presents preliminary evidence from both the human and animal literatures to support this new model. Specific topics reviewed include: psychopathology related to the menstrual cycle, anxiety sensitivity and its relationship to the menstrual cycle, PMS, and PMDD, anxiety-modulating effects of progesterone and its neuroactive metabolite, allopregnanolone, and how results from the neuroendocrine literature relate to psychopathology or symptoms associated with the menstrual cycle.

Premenstrual distress predicts panic-relevant responding to a CO2 challenge among young adult females

The current study examined the incremental validity of self-reported premenstrual distress in predicting panic responsivity (self-reported panic symptoms and skin conductance response frequency; SCR) following inhalation of 10% CO(2)-enriched air. A community sample of young adult women (n=46) completed questionnaires assessing substance use patterns, premenstrual symptoms and distress, and anxiety sensitivity and underwent a laboratory biological challenge procedure (4-min 10% CO(2)-enriched air inhalation). As hypothesized, higher premenstrual distress scores significantly predicted greater self-reported panic symptoms following the CO(2) challenge above and beyond other theoretically relevant variables (anxiety sensitivity, cigarette use, and alcohol consumption). In predicting SCR, premenstrual distress exhibited only a trend towards statistical significance. These findings provide preliminary evidence that premenstrual symptoms may serve as a potential risk factor to experience more intense panic symptoms in response to perturbations in bodily sensations.

Prenatal fear of childbirth and anxiety sensitivity

OBJECTIVE

Fear of childbirth (FOC) or what is historically referred to as tokophobia (a phobic state where a woman avoids childbirth despite desperately wanting a baby), is known to complicate the delivery process. In this study, the relationship of Anxiety Sensitivity (AS) to FOC was examined given that AS is a risk factor for other fears. Specifically, the contribution of three AS dimensions (physical, psychological or social concerns) relative to other factors (e.g., parity of the mother, trait anxiety) in accounting for FOC was explored.

METHODS

Women in their final 4 months of pregnancy (n = 110) completed the Anxiety Sensitivity Index, the State-Trait Anxiety Inventory-Trait Scale and the Wijma Delivery Expectancy/Experience Questionnaire.

RESULTS

Most demographic variables were non-significant in predicting FOC with the exception of participants' parity. Multiple regression analysis revealed that AS-physical concerns significantly predicted elevated FOC even after controlling for parity and trait anxiety; higher levels of AS-physical concerns, higher trait anxiety, and expecting a first child all independently predicted greater FOC.

CONCLUSION

Variance in FOC is explained, in part, by AS-physical concerns. Further, AS-physical concerns are distinct from trait anxiety in predicting FOC. Similar to other fears, the results support the possibility that AS may be a risk factor for elevated FOC.

Predicting anxious response to a social challenge and hyperventilation: comparison of the ASI and ASI-3

This study compared the predictive ability of the original ASI to the ASI-3 and measures of trait and social anxiety in two challenge conditions; hyperventilation or a social challenge. During hyperventilation, the ASI-3 social concerns subscale was a better predictor than the subscales of the original ASI and measures of general trait and social anxiety. During the social manipulation, results indicated the ASI-3 social concerns subscale and the social anxiety measure were significant predictors of anxious response. Results provide evidence that the ASI-3 is an improvement over the original ASI and is a sound overall measure of response to challenge procedures.

The structure of emotional and cognitive anxiety symptoms

A sample of 327 patients with primary panic disorder or social phobia completed a questionnaire comprising 77 emotional and cognitive anxiety symptoms from which 12 index scales were constructed. Explorative factor analysis yielded two factors, but confirmatory factor analysis indicated that the factor solution was not invariant across diagnoses. Nevertheless, the two-factor structures fitting data from patients with panic disorder and social phobia, respectively, had similarities in content. The first factor, emotions and cognitive-social concerns, comprised emotional expressions (sadness, fear, and anger), cognitions about cognitive dysfunction (difficulty concentrating, confusion, and loss of control) and social phobic cognitions. It was positively correlated with severity of bodily anxiety symptoms and with the neuroticism personality trait. The second factor, fear of physical sensations, was positively correlated with a cardio-respiratory dimension of bodily anxiety symptoms in panic disorder, lending support to the hypothesis of specific threat-relevant links between bodily symptoms and catastrophic cognitions.

Panic disorder subtypes: further clinical differences

Panic disorder (PD) is a heterogeneous phenomenon with respect to symptom profile. Most studies agree that a group of patients with prominent respiratory symptoms emerged as a distinct PD subtype. In this study we compared a range of clinical features associated with PD and agoraphobia in patients with respiratory (RS) and nonrespiratory (NRS) subtypes of PD. The participants were 124 patients with PD (79 women and 45 men), with or without agoraphobia, diagnosed by DSM-IV criteria. Following the observer-rated Panic Disorder Severity Scale assessment, subjects completed self-report measures, including the Anxiety Sensitivity Index (ASI), Panic-Agoraphobia Scale; the Beck Anxiety Inventory; and the Panic-Agoraphobic Spectrum Scale (PAS-SR). Multivariate analysis of variance (MANOVA) showed significant group differences [Pillai's trace = 0.95, F (5, 118)(=)2.48, P = .036]. Patients in RS group had higher mean total scores on the ASI (F = 5.00, df = 1, P = .027) and PAS-SR (F = 11.23, df = 1, P = .001) than patients in NRS group. Also, patients with RS attained higher scores than patients with NRS on four domains of PAS-SR (panic-like symptoms, agoraphobia, separation sensitivity, and reassurance seeking). A descriptive discriminant analysis of the data correctly identified 69.4% of the patient group in general and 86.1% of RS group (Wilks's lambda = 0.87, df = 8, P = .048). The significant discriminating factors of the RS and NRS groups were domains of panic-like symptoms, agoraphobia, separation sensitivity, and reassurance seeking. Our findings suggest that anxiety sensitivity and panic-agoraphobic spectrum symptoms might be particularly relevant to understanding subtypes of PD.

Anxiety Sensitivity Amelioration Training (ASAT): a longitudinal primary prevention program targeting cognitive vulnerability

Fear of arousal symptoms, often referred to as anxiety sensitivity (AS) appears to be associated with risk for anxiety pathology and other Axis I conditions. Findings from a longitudinal prevention program targeting AS are reported. Participants (n=404) scoring high on the Anxiety Sensitivity Index (ASI) were randomly assigned to receive a brief intervention designed to reduce AS (Anxiety Sensitivity Amelioration Training (ASAT)) or a control condition. Participants were followed for up to 24 months. Findings indicate that ASAT produced greater reductions in ASI levels compared with the control condition. Moreover, reductions were specific to anxiety sensitivity relative to related cognitive risk factors for anxiety. ASAT also produced decreased subjective fear responding to a 20% CO(2) challenge delivered postintervention. Data from the follow-up period show a lower incidence of Axis I diagnoses in the treated condition though the overall group difference was not statistically different at all follow-up intervals. Overall, findings are promising for the preventative efficacy of a brief, computer-based intervention designed to decrease anxiety sensitivity.

Risk-factor research and prevention programs for anxiety disorders: A translational research framework

The aim of the present essay is to discuss the interconnection between risk-factor research and prevention program development for panic-spectrum psychopathology. We argue that prevention of panic-spectrum psychopathology specifically, and anxiety disorders more generally, is likely to be best advanced through active, systematic translation of basic, risk-factor research. After operationalizing key terminology, we present some exemplar risk-factor candidates for panic-spectrum psychopathology, summarize research related to their role as risk-factors for panic problems, and link this discussion to risk-factor nomenclature. We then present a translational framework for extrapolating extant knowledge on these and other potential risk-factors for panic-spectrum psychopathology with respect to the development of preventative interventions. The proposed translational framework is intended to describe a forward-feeding process by which risk-factor research could be used by clinical researchers to inform prevention programs; and reciprocally, how such prevention knowledge could be most effectively utilized to drive new, clinically focused risk-factor research.

Is premenstrual dysphoria a variant of panic disorder? A review

Patients with premenstrual dysphoric disorder (PMDD) and patients with panic disorder (PD) both experience high rates of panic attacks in laboratory panic provocation studies. Recently, this shared elevated rate of challenge-induced panic has received increasing attention. Researchers have suggested that PMDD and panic disorder may share a pathophysiological or psychobiological link. The purpose of this paper is to review the findings from PMDD challenge studies and the theories advanced to connect PMDD to panic disorder. Taken together, the results of the PMDD challenge studies confirm that agents that incite panic in PD patients do so as well in PMDD women. This shared elevated challenge-induced panic cannot be accounted for by explanations such as a history of PD in PMDD women. None of the physiological theories as currently expressed--suffocation false alarm, gamma-aminobutyric acid (GABA), noradrenergic, serotonergic, and cholecystokinin--yet provides a compelling candidate to account for shared elevated challenge-induced panic in PD and PMDD patients. Psychological perspectives on panic emphasize that bodily sensations themselves can cause fear. Researchers have yet to apply several influential psychological approaches--conditioning, catastrophic misinterpretation, and anxiety sensitivity--to PMDD patients. Because psychological factors influence anxious responding in challenge studies, the search for the biological abnormality best accounting for PMDD panic might benefit from a reframing of the question to one that considers the psychological perspective as well.

Anxiety sensitivity as a predictor of panic attacks

Anxiety sensitivity (AS) is the fear of physical symptoms of anxiety and related sensations believed to have harmful consequences. AS may play a central role in the nature and etiology of panic disorder (PD) and the genesis of panic attacks. We collected Anxiety Sensitivity Index (ASI) scores from PD patients and controls to determine if AS accurately predicts panic. ASIs were completed prior to panic induction using the modified Read rebreathing test in both hypoxic and hyperoxic conditions. Total scores first-order factors, and individual item ASI scores were correlated with panic presence (Spearman correlation) for each of the hypoxic and hyperoxic rebreathing tests for both study populations. Control subjects' data correlated significantly for items 4, 8, and 11 of the ASI for the hyperoxic (n=9; r(S)=0.63, 0.70, and 0.63, respectively) and items 4 and 8 for the hypoxic rebreathing tests (n = 9; r(S) = 0.63 and 0.70, respectively). Panic patients' data correlated significantly for item 1 of the ASI for hyperoxic tests (n=8; r(S)=0.76) and item 5 for the hypoxic tests (n = 8; r(S) = 0.95). Total ASI scores or first-order factors (physical, social concerns, and mental incapacitation) scores of either study group did not correlate significantly with panic presence. AS may not be a reliable predictor of panicogenic responses to CO2-induced panic in either PD or normal control populations. AS may not be an ultimate causal element in eliciting panic attacks.

Attentional bias to threat and emotional response to biological challenge

Attentional bias towards threat reliably correlates with clinical anxiety status as well as elevated trait anxiety. Although such findings have led many to posit a potential causative or predictive role of threat-biased attentional processes on anxiety problems, little informative research exists. The present investigation was designed to address the role of threat-biased attentional processes on emotional/fearful responding. Eighty-seven participants provided baseline measures of anxiety vulnerability (i.e., anxiety sensitivity; unmasked/masked emotional Stroop task indices) and then underwent biological challenge procedures (inhalations of 20% carbon dioxide (CO2)-enriched air). Following challenge, participants completed measures of emotional response. Regression analyses indicated that both unmasked and masked attentional bias indices significantly predicted emotional responding above and beyond anxiety sensitivity. Exploratory analyses also revealed a gender effect, with prediction of emotional response largely attributable to females. These findings support attentional bias towards threat as a relatively independent factor predictive of emotional responding.

The effects of anxious responding on mental arithmetic and lexical decision task performance

Anxiety-related responding and skill deficits historically are associated with performance-based problems such as mathematics anxiety, yet the relative contribution of these variables to substandard performance remains poorly understood. Utilizing a 7% carbon dioxide (CO2) gas to induce anxiety, the present study examined the impact of anxious responding on two performance tasks, mental arithmetic and lexical decision. Independent variables included math anxiety group, gender, and gas condition. Dependent variables included task performance and physiological and self-report indices of anxiety. A total of 64 university undergraduate students participated. Physiological and verbal-report measures of anxiety supported the utility of 7% carbon dioxide-enriched air as an anxiety-inducing stimulus. Behavioral disruption on performance tasks, however, did not differ as a function of carbon dioxide inhalation. Performance did differ as a function of math anxiety. High math anxious individuals generally exhibited higher error rates on mathematical tasks, particularly on tasks designed to measure advanced math skill and those requiring working memory resources. These findings are discussed with reference to processing efficiency theory, discordance among anxiety response systems, and the intricacies associated with skill measurement.

Differential sensitivity of the three ASI factors in predicting panic disorder patients' subjective and behavioral response to hyperventilation challenge

The overall aim of the present investigation was to examine the association between the subscales of the ASI and emotional responding to voluntary hyperventilation challenge in a panic disorder population. Based on findings from [J. Abnorm. Psychol. 110 (2001) 372.], we predicted that the AS-Physical Concerns subscale would best predict the fear response to hyperventilation. We also examined the relative contribution of each of the three ASI subscales in predicting behavioral tolerance to hyperventilation. Participants (N = 192) meeting DSM-IV criteria for panic disorder with or without agoraphobia completed the Anxiety Sensitivity Index (ASI) and underwent a voluntary hyperventilation challenge. Consistent with prediction, the AS-Physical subscale significantly predicted subjective fear during the hyperventilation challenge (12% of variance accounted for); whereas only the AS-Social subscale accounted for significant variance (4%) in patients' behavioral tolerance to the hyperventilation challenge.

Factor Structure and Reliability of the Anxiety Sensitivity Profile in a Turkish Sample1

Summary: Anxiety sensitivity is an individual difference variable defined as the fear of fear or the fear of anxiety, arising from the belief that the experience of anxiety symptoms leads to illness or additional anxiety. The Anxiety Sensitivity Profile (ASP) is a 60 item self-report measurement, and each item is assessed on a 7-point scale. The purpose of this study is to determine the factor structure and reliability of the Turkish version of the ASP. To address this purpose, first the scale was translated into Turkish, and then it was administered to 434 university students. Principal components factor analysis with promax rotation revealed four factors in which all items had a factor loading of 0.30 or more. The factors were as follows: (1) fear of respiratory symptoms, (2) fear of cognitive dyscontrol, (3) fear of cardiac symptoms, and (4) fear of gastrointestinal symptoms. The internal consistency of these four factors was 0.97, 0.93, 0.91, and 0.86, respectively. The overall scale also had a high degree of internal consistency, with an α coefficient of 0.98. Item-total analysis revealed that the internal consistency of all items was satisfactory (rs 0.30-0.77). Data provided evidence that the Turkish version of the ASP had a multidimensional construct with four lower order factors loaded on a higher order factor.

Cross cultural evaluation of smokers risk for panic and anxiety pathology: a test in a Russian epidemiological sample

The present study evaluated the main and interactive effects of level of smoking (cigarettes per day) and anxiety sensitivity (fear of anxiety and anxiety related sensations) in predicting panic and anxiety variables in an epidemiologically-defined sample of smokers from Moscow (n=95). The combination of high levels of anxiety sensitivity and smoking predicted agoraphobic avoidance, but not frequency of panic attacks during the past week. These findings suggest anxiety sensitivity may moderate the relation between level of smoking and prototypical panic psychopathology variables (panic attacks and agoraphobic avoidance) even after controlling for the theoretically-relevant factors of alcohol abuse and negative affect.

Anxiety sensitivity and 35% CO2 reactivity in patients with panic disorder

OBJECTIVE

The present study examines the possible relationships between anxiety sensitivity (AS) and reactivity to the 35% carbon dioxide (CO(2)) challenge in panic disorder (PD).

METHODS

One-hundred eight patients with PD underwent the 35% CO(2) challenge and completed the Anxiety Sensitivity Index (ASI). Multiple regression analyses were applied to evaluate the role of AS as a predictor of CO(2)-induced anxiety.

RESULTS

Fifty-six patients with PD showed high AS scores, whereas 48 showed medium scores and 4 low scores. ASI scores significantly predicted symptomatological reaction to CO(2) but not subjective induced anxiety.

CONCLUSION

These findings suggest that the fear of anxiety-related bodily sensations was related to the symptomatological reactivity to CO(2) but did not seem to play a crucial role in the modulation of the subjective anxiogenic/panicogenic response to hypercapnia in patients with PD.

Anxiety sensitivity and panic disorder

Anxiety sensitivity refers to fears of anxiety-related sensations. Most often measured by the Anxiety Sensitivity Index (ASI), anxiety sensitivity is a dispositional variable especially elevated in people with panic disorder. Regardless of diagnosis, ASI scores often predict panic symptoms in response to biological challenges (e.g., carbon dioxide inhalation) that provoke feared bodily sensations. Prospective longitudinal studies indicate that scores on the ASI predict subsequent spontaneous attacks, indicating that elevated anxiety sensitivity is a risk factor for panic and perhaps panic disorder. Cognitive behavioral treatment reduces anxiety sensitivity in panic patients, perhaps protecting against relapse. Imipramine likewise decreases anxiety sensitivity.

The Anxiety Sensitivity Index for Children: factor structure and relation to panic symptoms in an adolescent sample

This study examines the factor structure underlying the Anxiety Sensitivity Index for Children (ASIC. J Anxiety Disord, 12 (1998) 307) in an adolescent sample. Three-hundred-and-eight adolescents, aged 12 to 18, completed the ASIC and measures of anxiety and depression. Factor analysis of the ASIC items resulted in a two-factor structure that is similar to that reported by Laurent et al. These two factors included a physical concerns dimension and a mental concerns dimension similar to those found in studies of adult anxiety sensitivity. Subscales measuring these two factors demonstrated concurrent validity, showing particularly close associations with measures of panic symptoms. In addition, both of these subscales showed incremental validity in predicting panic symptoms after controlling for the other anxiety sensitivity subscale and a measure of depression. These results provide evidence that the anxiety sensitivity construct is applicable during adolescence and support the use of the ASIC.

The roles of alcohol and alcohol expectancy in the dampening of responses to hyperventilation among high anxiety sensitive young adults

Previous research suggests that high anxiety sensitivity (AS) young adults are particularly sensitive to alcohol's dampening effects on their responses to arousal-induction challenge [Alcohol.: Clin. Exp. Res. 24 (2000) 1656.]. This sensitivity to alcohol reward may place high AS individuals at increased risk for alcohol abuse. Over-and-above alcohol's pharmacological effects, tension-reduction expectancies might contribute to alcohol's reactivity-dampening effects in high-AS individuals. The present study examined the role of alcohol and alcohol expectancy factors by activating expectancies experimentally. Forty-eight high-AS young adults were randomly assigned to one of three beverage conditions: alcohol (pharmacology plus expectancy), placebo (expectancy only), and control (no pharmacology and no expectancy). Following beverage consumption and absorption, participants underwent a 3-min voluntary hyperventilation challenge. Replicating and extending previous findings, participants in the alcohol condition showed dampened affective and somatic responses to the challenge, and marginally dampened cognitive responses to the challenge, compared to both placebo and control participants. However, placebo participants did not display dampened responses to the challenge relative to control beverage condition participants. Additional analyses suggested that activation of tension-reduction expectancies might have contributed to an "inverse placebo" effect among high-AS participants administered placebo. Implications of the results for future research and for the prevention and treatment of alcohol problems among high-AS individuals are discussed.

The catastrophic misinterpretation model of panic disorder

In the catastrophic misinterpretation model of panic Clark [Behav. Res. Ther. 24(1986)1461] proposes that panic attacks result from the misinterpretation of autonomic arousal stimuli as precursors to a physical or psychological emergency. The model has been widely examined, with many researchers suggesting that this specific cognitive bias is implicated in both the phenomenon of panic, and the aetiology and maintenance of panic disorder. Various research methodologies have provided only partial or inconclusive support for the model as being uniquely associated with panic, and as a cognitive process underpinning the experience of panic. This paper reviews the body of existing evidence and its implications for the model and proposes future research directions. The influence of implicit operational definitions of key terms in the catastrophic misinterpretation literature (e.g. 'catastrophe', 'threat', 'anxiety-related') are examined, and clarifications proposed. Inconsistencies and limitations in the measurement of catastrophic misinterpretation are highlighted, and subsequently developments to measurement instruments are proposed.

The utility of the ASI factors in predicting response to voluntary hyperventilation among nonclinical participants

Empirical research has demonstrated that the Anxiety Sensitivity Index (ASI) contains three separable factors and that ASI total scores are useful in predicting response to physiological challenge procedures. Little is known, however, of the predictive capability of the ASI factors. This study investigated the utility of the three factors of the ASI compared to ASI total scores and the STAI-T, a more general measure of trait anxiety, in predicting response to hyperventilation. As expected, the ASI total score was a significant predictor of response to hyperventilation, while the STAI-T was not. Using multiple regression, when the physical concerns factor was entered first, the social concerns and mental incapacitation factors of the ASI were not significant predictors of response to hyperventilation. Furthermore, when the physical concerns factor was entered into a regression equation followed by the remainder of the ASI items, only the physical concerns factor remained a significant predictor of response to hyperventilation. These results suggest that while response to physiological challenge procedures is predicted by ASI total scores, it may be best predicted by the physical concerns factor, and that the mental incapacitation and social concerns subscales do not play key roles in predicting response to physiological challenge procedures.

Hyperventilation, anxiety sensitivity, and the expectations for alcohol use: subjective and physiological reactivity to alcohol cues

The present study examined the relation between alcohol-related expectancies, body sensation fear and reactions to cues for alcohol following a hyperventilation task. Forty-two undergraduate students participated for course credit. Each student hyperventilated for 5 min, paced at a rate of 30 breaths per minute. Following hyperventilation, each student was exposed to containers with alcohol (beer and wine coolers), with subjective urge to consume and heart rate measures taken. Path analysis supported models associated with tension reduction and self-focused attention expectancies as significant contributors to increased urge to consume alcohol and lowered heart rate following hyperventilation. However, social-anxiety-related expectancies failed to demonstrate a relationship. These results suggest that additional work on the tension reduction model of alcohol use should examine physiological stressors in association with subject characteristics such as proneness to experience panic symptoms.

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.

Anxiety sensitivity does not predict fearful responding to 35% carbon dioxide in patients with panic disorder

The aim of the present study was to examine the relationship between anxiety sensitivity, as measured by the Anxiety Sensitivity Index (ASI), and four dimensions of behavioural reactivity to a single inhalation of 35% carbon dioxide (CO(2)) in 31 patients with panic disorder. ASI scores correlated positively with baseline State-Trait Anxiety Inventory scores but did not correlate with post-CO(2) scores. Correlational analyses revealed a significant, albeit modest, correlation between anxiety sensitivity and cognitive symptoms induced with CO(2). However, no significant association was found between anxiety sensitivity and other dimensions of CO(2)-induced anxiety, including severity of somatic symptoms, subjective levels of anxiety, fear or apprehension, and fear of the somatic symptoms induced by CO(2). Overall, these data do not support the view that anxiety sensitivity plays a key role in mediating behavioural sensitivity to CO(2) inhalation in panic disorder.

Prospective evaluation of the etiology of anxiety sensitivity: test of a scar model

A large body of research has suggested that anxiety sensitivity (AS) acts as a specific vulnerability factor in the development of anxiety pathology. More recently, attention has turned to the etiology of AS per se. The present study represents a specific test of a Scar model of AS. A Scar model posits that the experience of distress will affect the vulnerability factor. We were specifically interested in evaluating the effects of a specific stressor (spontaneous panic) as well as general distress on changes in AS over time. A large nonclinical sample of young adults (N = 1296) was prospectively followed over a five week highly stressful period of time (i.e. military basic training). Findings were consistent with the Scar model and suggested that the specific stressor of experiencing a panic attack as well as general stressors creating significant anxiety symptoms uniquely contributed to increased levels of AS (regardless of prior history of panic). Moreover, the experience of spontaneous panic in the context of generally low levels of distress (both anxiety and depression) appeared to be particularly pernicious in terms of resulting in greater increases in AS. In sum, anxiety-related stressors appear to have the potential to 'scar' individuals in regard to this cognitive vulnerability factor.

Interaction of psychological type and anxiety sensitivity on academic achievement

The Myers-Briggs Type Indicator and the Anxiety Sensitivity Index were administered to 143 undergraduate college students. Analyses of variance were performed to assess the relationship between these indices and semester grades (Grade Point Average). The Myers-Briggs Sensing-Intuitive and Judging-Perceiving dimensions showed significant main effects on GPA. The interaction of Judging-Perceiving and Anxiety Sensitivity was also significant (F = 18.00, p<.0001), although that of Sensing-Intuition and Anxiety Sensitivity was not (F = 3.51, p=.06). These findings suggest that personality factors measured by the Myers-Briggs Type Indicator may serve as mediating variables in evaluating whether trait anxiety has a facilitating or debilitating effect on academic achievement.

Carbon dioxide inhalation challenges in idiopathic environmental intolerance

BACKGROUND

Idiopathic environmental intolerance (IEI) is associated with unexplained physical symptoms, which overlap considerably with those of panic disorder (PD).

OBJECTIVE

This study tested the hypothesis that patients with symptoms to suggest IEI exhibit features of PD in response to nonnoxious environmental stimuli.

METHODS

A single-blind, case-control 35% carbon dioxide inhalation challenge was conducted at a university-based occupational health unit with the use of standardized psychologic questionnaires involving 36 patients with IEI and 37 healthy control subjects. The main outcome measures included panic attack symptoms and scores on the Anxiety Sensitivity Index, a measure of panic-related anxiety.

RESULTS

Patients with IEI scored significantly higher on the Anxiety Sensitivity Index than control subjects did (P <.05). Significantly more patients with IEI (71%) than control subjects (26%) fulfilled panic attack criteria after carbon dioxide (P <.001). Physiologic responses to the challenge were not significantly different between groups.

CONCLUSIONS

Results suggest that, similar to patients with PD, patients with IEI display high anxiety sensitivity and in response to carbon dioxide inhalation tend to experience heightened anxiety and panic attacks.

Interoceptive accuracy and panic

Psychophysiological models of panic hypothesize that panickers focus attention on and become anxious about the physical sensations associated with panic. Attention on internal somatic cues has been labeled interoception. The present study examined the role of physiological arousal and subjective anxiety on interoceptive accuracy. Infrequent panickers and nonanxious participants participated in an initial baseline to examine overall interoceptive accuracy. Next, participants ingested caffeine, about which they received either safety or no safety information. Using a mental heartbeat tracking paradigm, participants' count of their heartbeats during specific time intervals were coded based on polygraph measures. Infrequent panickers were more accurate in the perception of their heartbeats than nonanxious participants. Changes in physiological arousal were not associated with increased accuracy on the heartbeat perception task. However, higher levels of self-reported anxiety were associated with superior performance.

The efficacy of habituation in decreasing subjective distress among high anxiety-sensitive college students

While there is mounting evidence that the concept of anxiety sensitivity (AS) is linked to the expression of anxiety (specifically, panic), there has been little research comparing the efficacy of interoceptive exposure alone with interoceptive exposure coupled with cognitive restructuring among high AS participants. The present investigation addressed this issue in a sample of high anxiety-sensitive college students (scores above 29 on the Anxiety Sensitivity Index). Participants were randomly assigned to receive either five consecutive trials of voluntary hyperventilation or five consecutive trials of hyperventilation with cognitive restructuring instructions. It was expected that while repeated hyperventilation would be associated with a significant reduction in self-reported anxiety, catastrophic cognitions, and somatic sensations across trials, the greatest reduction in symptoms would occur with the addition of cognitive restructuring. These predictions were partially supported. As expected, high AS participants evidenced significant decreases in anxiety symptoms when habituation was accompanied by cognitive restructuring. Contrary to predictions, however, interoceptive exposure alone was not effective in reducing anxious symptoms. These results suggest that brief habituation alone may not be an effective strategy for high AS participants and are discussed as providing further support for a cognitive model of anxiety.

Factor structure of a measure of anxiety sensitivity in children

Anxiety sensitivity (i.e., the disposition to react to autonomic arousal with fear) has taken a central role in recent conceptualizations of anxiety. However, questions regarding the dimensional nature of anxiety sensitivity remain. In particular, the factor structure of anxiety sensitivity is unexplored in nonadult populations. The factor structure of the Anxiety Sensitivity Index for Children (ASIC) was examined in three studies. Study 1 (N = 95) used a sample of school children in Grades 4-8 to investigate the reliability of items and factor structure. Items with weak psychometric properties were eliminated, and subsequent analyses revealed that the ASIC was best viewed as a hierarchical scale with a higher order factor (Anxiety Sensitivity) and two first-order factors (Fear of Physiological Arousal and Fear of Mental Catastrophe). Study 2 (N = 112) and Study 3 (N = 144) used more distressed samples of youngsters, and they also found the ASIC to be a hierarchical scale. These findings add a developmental perspective to the Anxiety Sensitivity Index factor analytic discussion and are highly consistent with emergent thinking in the adult anxiety sensitivity literature.

Validation of the French translation of the agoraphobic cognitions questionnaire

BACKGROUND

The goal of the present study was to validate the French version of the Agoraphobic Cognitions Questionnaire (ACQ).

METHODS

Subjects consisted of 115 patients with panic disorder and agoraphobia, 54 obsessive-compulsive patients and 72 normal controls. Patients were referred for outpatient treatment. They filled in the questionnaire before and after entering treatment. The control group consisted of people taken from the general population. It was matched with the clinical groups on age, sex and education.

RESULTS

The ACQ appears to have a constant factor structure across US, Dutch and French samples. Results support the validity of the total score of the ACQ. Patients with panic disorder and agoraphobia scored significantly higher than obsessive-compulsive patients and control subjects. On the ACQ physical concerns subscale agoraphobic patients were significantly different from obsessive-compulsive patients and control subjects. On the social/behavioural subscale agoraphobic patients and obsessive-compulsive patients were significantly different from control subjects. The French translation of the ACQ was found to be stable over an interval of 15 days in the control group. The Cronbach coefficients of both subscales were also satisfactory. These results support the stability and the internal consistency of the questionnaire. In addition, the French translation of the ACQ was sensitive to changes with cognitive-behavioural therapy.

CONCLUSIONS

These results support the findings of Chambless and Gracely [Cogn Ther Res 1989;13:9-20]. The ACQ physical concerns subscale is a specific feature for the anxiety status experienced by patients with panic disorder and agoraphobia. The ACQ social/behavioural subscale seems to be a more general feature of anxious patients.

Anxiety sensitivity and response to hyperventilation challenge: physiologic arousal, interoceptive acuity, and subjective distress

Twenty-four female undergraduates, 12 high on anxiety sensitivity and 12 low on anxiety sensitivity, were subjected to a hyperventilation challenge task. Physiologic and subjective measures of arousal and distress were obtained before, during, and after the hyperventilation challenge. Alternating between the eight 15-second intervals of hyperventilation, participants engaged in a heartbeat-tracking task for eight 10-second intervals to assess interoceptive acuity. Although the hyperventilation challenge produced phase main effects for physiologic arousal, and group and time main effects for subjective distress, there were no significant interaction effects. Results revealed no significant interoceptive acuity differences across the low and high anxiety sensitivity groups. However, subjective ratings of physiological sensations during hyperventilation were significantly greater for the high anxiety sensitivity group. Hierarchical multiple regression analyses revealed that anxiety sensitivity accounted for additional variance beyond trait anxiety in explaining subjective ratings of arousal and distress in this nonclinical sample in response to a hyperventilation challenge.

Psychophysiological assessment of respiratory function in panic disorder: evidence for a hyperventilation subtype

OBJECTIVE

Previous research has found differences in respiratory function between panic disorder and other anxiety disorder populations. These differences have been explained as reflecting either a) a specific feature of panic disorder, b) merely a sign of increased general arousal, or c) a result of population sampling error. The current study addressed the question of such differences by using improved methodology over previous research. A preliminary evaluation of respiratory symptoms during panic attacks was undertaken as a means of identifying a respiratory-sensitive subtype of the panic patient.

METHOD

Seventeen panic disorder patients (PD), 18 patients with generalized anxiety disorder (GAD), and 20 normal control (NC) subjects were administered a psychophysiological evaluation composed of baseline, stressor, and recovery phases. Panic patients were measured for the severity of respiratory symptoms during panic attacks. End-tidal CO2 (EtCO2) and respiration rate were measured throughout the psychophysiological evaluation.

RESULTS

PDs demonstrated significantly lower baseline EtCO2 levels than the GADs and NCs, in spite of being equivalent to GADs on baseline anxiety levels. Moreover, panic patients reporting a high level of respiratory symptoms during panic attacks seemed to account for the bulk of observed differences.

CONCLUSIONS

These findings lend support to a group of studies showing differences in respiratory function between panic disorder and other anxiety disorder populations. In addition, this study provides preliminary support for the presence of a distinct "hyperventilation subtype" of panic disorder. The implications of these findings for future research and treatment are discussed.

Emotional and cognitive factors connected with response to cholecystokinin tetrapeptide in healthy volunteers

This article examines the effect of baseline anxiety, anxiety sensitivity and dysfunctional attitudes on the response to cholecystokinin tetrapeptide (CCK-4) in healthy volunteers. CCK-4 and placebo were administered to 14 subjects in a double-blind manner. Four volunteers experienced a panic attack after CCK-4 administration. Those subjects who panicked had significantly higher baseline scores on dysfunctional attitudes. Dysfunctional thought patterns appeared also to predict number of symptoms and experience of cognitive and affective symptoms during injection. Baseline anxiety as well as anxiety sensitivity predicted reactions to placebo but not panic responses to CCK-4. Results suggest that a general tendency towards erroneous interpretation of information has some role in mediating the panicogenic effects of CCK-4, and also interpersonal sensitivity may constitute a vulnerability factor for panic. Psychological factors that have been considered more specific to panic disorder, namely high state and trait anxiety as well as anxiety sensitivity, appeared mainly to determine general reactions to a threatening situation.

Fearful responding to repeated CO2 inhalation: a preliminary investigation

In an effort to explore factors which maintain fear of physical sensations, repeated administration of 35% CO2 was used with college students scoring high and low on the Anxiety Sensitivity Index. Half of each group was administered 12 CO2 trials, while the other half received 9 CO2 trials, followed by a dishabituation trial (Trial 10) and 2 more CO2 administrations (Trials 11 and 12). Measures included subjective anxiety, heart rate, skin conductance, and number of panic symptoms reported. Results indicated a nonsignificant trend for the High ASI group to show increased pre-inhalation anxiety across trials, while the Low ASI group showed a rapid reduction in pre-inhalation anxiety. Post-inhalation skin conductance mirrored this pattern, although rapid reduction in post-inhalation heart rate was observed. Overall, the High ASI participants showed a notable lack of fear reduction across trials. Results are discussed in light of sensitization as a factor contributing to anticipatory anxiety, with implications for understanding the etiology and maintenance of Panic Disorder.

Anxiety sensitivity, suffocation fear, trait anxiety, and breath-holding duration as predictors of response to carbon dioxide challenge

We investigated predictors of response to carbon dioxide challenge (i.e. breathing deeply and rapidly into a paper bag for 5 min) in college students. Zero-order correlations indicated that scores on both the Anxiety Sensitivity Index (ASI: Reiss, Peterson, Gursky & McNally, 1986) and the Suffocation Fear Scale (SFS: Rachman & Taylor, 1994), predicted anxious response to challenge, whereas a behavioral measure of carbon dioxide sensitivity (i.e. maximum breath-holding duration) and scores on the State-Trait Anxiety Inventory--Trait form (STAI-T: Spielberger, Gorsuch, Lushene, Vagg & Jacobs, 1983) did not. Multiple regression revealed that all four variables remained in the model, entering in the following order: ASI, breath-holding duration, SFS, and STAI-T. These data suggest that psychological variables reflecting fears of bodily sensations are better predictors of response to challenge than either behavioral sensitivity to carbon dioxide or general trait anxiety.

Intrapatient agreement on phenomenology of panic attacks

Panic disorder is common in primary care settings and such a physician is often a patient's initial contact with the health care system. Previous work concerning the homogeneity of panic phenomenology across patients is contradictory. The purpose of this pilot study was to assess the intrapatient homogeneity of panic attacks and to examine associations between measures of homogeneity and physicians' confidence in the diagnosis. Ten patients meeting DSM-III-R criteria for panic disorder completed a diary documenting the symptomatic phenomenology of five consecutive panic attacks. In addition, the physician rated his diagnostic confidence for each patient. Patterns of symptoms and their sequences during panic showed good agreement within patients as did patterns of abatement and of presence of a precipitating event. The physician's diagnostic confidence was inversely related to agreement on symptom severity and variance of duration of an attack. This study suggests intrapatient homogeneity on most measures.