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

The benefits of being mindful: trait mindfulness predicts less stress reactivity to suppression

BACKGROUND AND OBJECTIVES

There has been a recent proliferation of research evaluating the efficacy of mindfulness as a clinical intervention. However, there is still little known about trait mindfulness, or how trait mindfulness interacts with maladaptive emotion regulation strategies. The current study further explores the effect of trait mindfulness on emotion regulation, as well as whether specific factors of trait mindfulness are uniquely associated with subjective and autonomic reactivity to stress.

METHODS

Forty-eight healthy male participants were trained in the use of the suppression strategy and then instructed to suppress their responses to the inhalation of a 15% CO2-enriched air mixture for 90 s while their subjective distress and heart rate were recorded.

RESULTS

After controlling for anxiety-related variables, the ability to provide descriptions of observed experiences predicted less heart rate reactivity to CO2 inhalation, while skillfulness at restricting attention to the present moment was uniquely predictive of less subjective distress. The tendency to attend to bodily or sensory stimuli predicted greater distress during CO2 inhalation.

LIMITATIONS

The inclusion of only healthy males limits the generalizability of study findings. Also, the sample size was relatively small.

CONCLUSIONS

These findings suggest that factors associated with trait mindfulness predict less stress reactivity and distress while engaging in suppression above and beyond other variables that have been shown to predict anxious responding. The implications for emotion and clinical research are discussed.

Hypersensitivity to hypercapnia: definition/(s)

Empirical evidence indicates that panic disorder (PD) patients experience hypersensitivity to hypercapnia, a condition in which the blood level of carbon dioxide exceeds the normal value. The importance of this research line is substantial and indeed, hypercapnic hypersensitivity has been advanced as a possible endophenotype of panic. Definitions of "hypersensitivity," however, have varied. The purpose of this brief review is to delineate and critique different definitions of hypercapnic hypersensitivity. Several definitions - panic attack rate, panic symptoms including dyspnea, subjective anxiety, and respiratory disturbance - are explored. The review concludes that although no ideal definition has emerged, marked anxiety post-hypercapnia has substantial support as a putative trait marker of PD. The term "subjective hypersensitivity" (Coryell et al., 2001) is re-introduced to denote pronounced anxiety post-hypercapnia and recommended for use along with its previous definition: increased self-reported anxiety measured on a continuous visual analog scale, already widely in use. Due to the well-established link between panic and respiration, definitional candidates focusing on aberrant respiratory response - less investigated as trait markers of PD in high risk studies - warrant scrutiny as well. Several reasons why definitional clarity might be beneficial are presented, along with ideas for future research.

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.

Effects of threat context and cardiac sensitivity on fear responding to a 35% CO2 challenge: a test of the context-sensitivity panic vulnerability model

The present study tested several predictions of a context-sensitivity panic vulnerability model emphasizing the interaction between threat context and threat sensitivities. Participants without a history of panic (N=47) completed both global and domain-specific panic relevant sensitivity measures and were then randomized to undergo a 35% CO2 inhalation challenge in the presence or absence of a cardiac defibrillator (threat context). As predicted by the model, cardiac sensitivity (but not trait anxiety or anxiety sensitivity) potentiated the effects of the presence of the defibrillator on CO2 fear responding. Moreover, as predicted by the model, the observed potentiation effects of cardiac sensitivity on CO2 fear responding were mediated by participants' threat appraisals connected to the presence of the defibrillator. Theoretical and clinical implications are discussed.

Temporal and structural dynamics of anxiety sensitivity in predicting fearful responding to a 35% CO2 challenge

The current study assessed the incremental prediction of anxiety sensitivity (AS) in both taxonic (categorical) and dimensional representations at various time points before and after a single vital capacity inhalation of a 35% CO(2), 65% balanced O(2) gas mixture. Participants were 128 young adults screened for a history of panic attacks. By controlling for traitwise factors including state anxiety and testing both categorical and continuous conceptualizations of the AS construct at various timepoints, the present report was able to evaluate the temporal and structural dynamics of AS in relation to fearful responding to the challenge. Relevant variables were evaluated in a hierarchical linear regression framework, and it was found that a continuous conceptualization of AS provided incremental predictive validity above and beyond trait anxiety immediately post-challenge, while a categorical representation of AS was equivalent to a continuous model of AS at post-challenge but outperformed a continuous model at follow-up. These data provide basic but important evidence suggesting that AS is uniquely associated with anxious responding to a 35% CO(2) challenge, and that categorical representations of AS should be considered in biological challenge studies.

The effects of acute exercise on CO(2) challenge reactivity

The present study examined the effects of acute exercise on anxiogenic responding to 65% O(2)/35% CO(2) challenge. Participants (N=92) were 51 female and 41 male volunteers ranging in age from 17 to 24 (M=19.43, SD=1.31). Participants had no history of panic attacks and were randomized to moderate treadmill exercise (i.e., 70% of HR(max)) or quiet rest prior to taking a single vital capacity inhalation of 35% CO(2)/65% O(2). Gender and measures of negative affectivity and anxiety sensitivity were included in the design as control variables. Results indicated participants who exercised prior to challenge showed significantly reduced reactivity compared to their counterparts who rested prior to challenge. Importantly, the effect sizes for the advantage of exercise over rest remained in the medium to large range (i.e., partial eta(2)>.07) after controlling for the effects of gender, anxiety sensitivity, and negative affectivity. These findings are the first to demonstrate that the anti-panic effects of exercise are unique from, and cannot be better explained by, established risk factors of CO(2) challenge reactivity.

Anxiety sensitivity and CO2 challenge reactivity as unique and interactive prospective predictors of anxiety pathology

Emerging evidence suggests that anxiety sensitivity (AS) and CO(2)-induced fear reactivity are associated with panic attacks and anxiety disorders. However, evidence regarding the unique and potentially synergistic effects of these variables is currently lacking. Our primary aims in this study were to determine whether AS and CO(2)-induced fear reactivity are unique and potentially interactive vulnerability factors involved in the pathogenesis of panic attacks and anxiety psychopathology. A large nonclinical sample of young adults (N=404) was prospectively followed over approximately 2 years. AS (i.e., 16-item Anxiety Sensitivity Index total scores) and biological challenge reactivity [i.e., fearful responding to pre- and postchallenge changes in subjective units of distress (SUDS) to a 20-s 20% CO(2) challenge] at study entry served as the primary predictor variables. Consistent with expectation, AS and challenge reactivity correlated only moderately with one another. Challenge reactivity was uniquely associated with the development of spontaneous panic attacks, whereas AS was uniquely associated with anxiety disorder diagnoses, including panic disorder. Moreover, the combination of both risk factors predicted spontaneous panic attacks beyond the effects of either risk factor individually. These data provide novel evidence for the unique and combined effects of AS and CO(2)-induced fear reactivity as risk factors in the development of anxiety and its disorders.

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.

Anxiety sensitivity in first-degree relatives of patients with panic disorder

Anxiety sensitivity (AS) has been proposed as a risk factor for the development of panic disorder. Strong familial-genetic influences in panic disorder (PD) have been reported. AS may be familial too. The current study therefore examined whether first-degree relatives of PD patients are more anxiety-sensitive than normals. Twenty-three first-degree relatives of PD patients, 38 PD patients and 30 normals were given the Anxiety Sensitive Index and the Body Sensations Questionnaire. It was found that the first-degree relatives were, indeed, more anxiety-sensitive than the normals, but less so than the PD patients, suggesting that AS runs in families.

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.