How good are patients with panic disorder at perceiving their heartbeats?

Interoceptive sensitivity, body image dissatisfaction, and body awareness in healthy individuals

Relationships among interoceptive sensitivity (IS), body image dissatisfaction, body mass index (BMI), and self-reported body awareness were investigated in a cross-sectional study. Eighty-two Norwegian high school students and 70 Hungarian undergraduate university students participated in the study. Subjects completed two questionnaires (Body Image Ideals Questionnaire - BIQ; Body Awareness Questionnaire - BAQ) followed by the assessment of interoceptive sensitivity using the Mental Tracking Method (MTM). An inverse, medium-level relationship between body image dissatisfaction and IS was found in both the Norwegian and the Hungarian samples. The relationships between IS and self-reported body awareness, and between body image dissatisfaction and BMI were uniformly non-significant in both samples. Predictors of body image dissatisfaction were resting heart rate, gender, and IS in the regression analysis after controlling for BMI, age, and nationality. The negative relationship between IS and body image dissatisfaction described in patients with anorexia nervosa also exists in healthy individuals. There is no direct connection between IS and self-reported body awareness.

Monitoring emotion through body sensation: a review of awareness in Goenka's Vipassana

Awareness is one of the two most important abilities cultivated in Goenka's Vipassana meditation, which refers to sensitivity to subtle bodily sensations and the associated psychological processes. This sensitivity and its derived function of monitoring emotion are not of notable concern in modern mindfulness-based psychotherapies. Evidence supports that Vipassana meditation truly enhances sensitivity to bodily sensations, but further study is required to assess the awareness of psychological processes. The value of monitoring mental processing has been widely accepted in psychology, as has enhanced sensitivity along with the potential dangers to mental health. Implications for practice and future studies are discussed.

Etiology, triggers and neurochemical circuits associated with unexpected, expected, and laboratory-induced panic attacks

Panic disorder (PD) is a severe anxiety disorder that is characterized by recurrent panic attacks (PA), which can be unexpected (uPA, i.e., no clear identifiable trigger) or expected (ePA). Panic typically involves an abrupt feeling of catastrophic fear or distress accompanied by physiological symptoms such as palpitations, racing heart, thermal sensations, and sweating. Recurrent uPA and ePA can also lead to agoraphobia, where subjects with PD avoid situations that were associated with PA. Here we will review recent developments in our understanding of PD, which includes discussions on: symptoms and signs associated with uPA and ePAs; Diagnosis of PD and the new DSM-V; biological etiology such as heritability and gene×environment and gene×hormonal development interactions; comparisons between laboratory and naturally occurring uPAs and ePAs; neurochemical systems that are associated with clinical PAs (e.g. gene associations; targets for triggering or treating PAs), adaptive fear and panic response concepts in the context of new NIH RDoc approach; and finally strengths and weaknesses of translational animal models of adaptive and pathological panic states.

Rumination and interoceptive accuracy predict the occurrence of the thermal grill illusion of pain

Background

While the neurophysiological mechanisms underlying the thermal grill illusion of pain (TGI) have been thoroughly studied, psychological determinants largely remain unknown. The present study aimed to investigate whether cognitive and affective personality traits encompassing rumination, interoception, and suggestibility may be identified as characteristics favouring the elicitation of paradoxical pain experiences.

Methods

The dominant hand of 54 healthy volunteers was stimulated with a water-bath driven thermal grill providing an interlaced temperature combination of 15 and 41°C. Pain intensity and pain unpleasantness perceptions were rated on a combined verbal-numerical scale (NRS). Traits were assessed via questionnaires, the heartbeat-tracking task, and warmth suggestions.

Results

Logistic regression analyses uncovered trait rumination and interoceptive accuracy (IA) as major predictors of the likelihood of the illusive pain occurrence (all p < .05). Rumination and suggestibility had an impact on unpleasant pain perceptions.

Conclusion

Our findings allowed identifying psychological factors substantially involved in the individual pre-disposition to reporting painful sensations in the thermal grill paradigm. These psychological characteristics may also be relevant in the context of central neuropathic pain, which to a large extent incorporates the same neural pathways.

Internal focus of attention in anxiety-sensitive females up-regulates amygdale activity: an fMRI study

Cognitive behavioral models of panic disorder (PD) stress the importance of an increased attentional focus towards bodily symptoms in the onset and maintenance of this debilitating anxiety disorder. In this fMRI mental tracking paradigm, we looked at the effects of focusing one's attention internally (interoception) vs. externally (exteroception) in a well-studied group at risk for PD-that is anxiety-sensitive females (AS-high). We hypothesized that AS-high subjects compared to control subjects will present higher arousal and decreased valence scores during interoception and parallel higher activity in brain areas which are associated with fear and interoception. 24 healthy female students with high levels of anxiety sensitivity and 24 healthy female students with normal levels of anxiety sensitivity serving as control group were investigated by 3 T fMRI. Subjects either focused their attention on their heartbeats (internal condition) or on neutral tones (external condition). Task performance was monitored by reporting the number of heartbeats or tones after each block. State of arousal and emotional valence were also assessed. The high anxiety-sensitive group reported higher arousal scores compared to controls during the course of the experiment. Simultaneously, fMRI results indicated higher activation in anxiety-sensitive participants than in controls during interoception in a network of cortical and subcortical brain regions (thalamus, amygdala, parahippocampus) that overlaps with known fear circuitry structures. In particular, the activity of the right amygdala was up-regulated. Future prospective-longitudinal studies are needed to validate the role of the amygdala for transition to disorder. Attention to internal body functions up-regulates the activity of interoceptive and fear-relevant brain regions in anxiety-sensitive females, a high-risk group for the development of anxiety disorders.

The impact of cardiac perception on emotion experience and cognitive performance under mental stress

Mental stress evokes several physiological responses such as the acceleration of heart rate, increase of electrodermal activity and the release of adrenaline. Moreover, physiological stress responses interact with emotional and behavioral stress responses. In the present study we provide evidence that viscero-sensory feedback from the heart (cardiac perception) is an important factor modulating emotional and cognitive stress responses. In our study, we compared participants with high versus low cardiac perception using a computerized mental stress task, in which they had to respond to rapidly presented visual and acoustic stimuli. Additionally, we assessed physiological responses (heart rate, skin conductance). Participants high in cardiac perception reported more negative emotions and showed worse task performance under the stressor than participants low in cardiac perception. These results were not moderated by physiological responses. We conclude that cardiac perception modulates stress responses by intensifying negative emotions and by impairing cognitive performance.

Suppression of the auditory N1-component for heartbeat-related sounds reflects interoceptive predictive coding

Although many studies have elucidated the neurocognitive mechanisms supporting the processing of externally generated sensory signals, less is known about the processing of interoceptive signals related to the viscera. Drawing a parallel with research on agency and the perception of self-generated action effects, in the present EEG study we report a reduced auditory N1 component when participants listened to heartbeat-related sounds compared to externally generated sounds. The auditory suppression for heartbeat sounds was robust and persisted after controlling for ECG-related artifacts, the number of trials involved and the phase of the cardiac cycle. In addition, the auditory N1 suppression for heartbeat-related sounds had a comparable scalp distribution as the N1 suppression observed for actively generated sounds. This finding indicates that the brain automatically differentiates between heartbeat-related and externally generated sounds through a process of sensory suppression, suggesting that a comparable predictive mechanism may underlie the processing of heartbeat and action-related information. Extending recent behavioral data about cardio-visual integration, the present cardio-auditory EEG data reveal that the processing of sounds in auditory cortex is systematically modulated by an interoceptive cardiac signal. The findings are discussed with respect to theories of interoceptive awareness, emotion, predictive coding, and their relevance to bodily self-consciousness.

Enhanced cardiac perception predicts impaired performance in the Iowa Gambling Task in patients with panic disorder

OBJECTIVE

Somatic marker theory predicts that somatic cues serve intuitive decision making; however, cardiovascular symptoms are threat cues for patients with panic disorder (PD). Therefore, enhanced cardiac perception may aid intuitive decision making only in healthy individuals, but impair intuitive decision making in PD patients.

METHODS

PD patients and age-and sex-matched volunteers without a psychiatric diagnosis (n = 17, respectively) completed the Iowa Gambling Task (IGT) as a measure of intuitive decision making. Interindividual differences in cardiac perception were assessed with a common mental-tracking task.

RESULTS

In line with our hypothesis, we found a pattern of opposing associations (Fisher's Z = 1.78, P = 0.04) of high cardiac perception with improved IGT-performance in matched control-participants (r = 0.36, n = 14) but impaired IGT-performance in PD patients (r = -0.38, n = 13).

CONCLUSION

Interoceptive skills, typically assumed to aid intuitive decision making, can have the opposite effect in PD patients who experience interoceptive cues as threatening, and tend to avoid them. This may explain why PD patients frequently have problems with decision making in everyday life. Screening of cardiac perception may help identifying patients who benefit from specifically tailored interventions.

Baseline heartbeat perception accuracy and short-term outcome of brief cognitive-behaviour therapy for panic disorder with agoraphobia

BACKGROUND

Increased heartbeat perception accuracy (HBP-accuracy) may contribute to the pathogenesis of Panic Disorder (PD) without or with Agoraphobia (PDA). Extant research suggests that HBP-accuracy is a rather stable individual characteristic, moreover predictive of worse long-term outcome in PD/PDA patients. However, it remains still unexplored whether HBP-accuracy adversely affects patients' short-term outcome after structured cognitive behaviour therapy (CBT) for PD/PDA.

AIM

To explore the potential association between HBP-accuracy and the short-term outcome of a structured brief-CBT for the acute treatment of PDA.

METHOD

We assessed baseline HBP-accuracy using the "mental tracking" paradigm in 25 consecutive medication-free, CBT-naive PDA patients. Patients then underwent a structured, protocol-based, 8-session CBT by the same therapist. Outcome measures included the number of panic attacks during the past week, the Agoraphobic Cognitions Questionnaire (ACQ), and the Mobility Inventory-Alone subscale (MI-alone).

RESULTS

No association emerged between baseline HBP-accuracy and posttreatment changes concerning number of panic attacks. Moreover, higher baseline HBP-accuracy was associated with significantly larger reductions in the scores of the ACQ and the MI-alone scales.

CONCLUSION

Our results suggest that in PDA patients undergoing structured brief-CBT for the acute treatment of their symptoms, higher baseline HBP-accuracy is not associated with worse short-term outcome concerning panic attacks. Furthermore, higher baseline HBP-accuracy may be associated with enhanced therapeutic gains in agoraphobic cognitions and behaviours.

Closing the gap between the inside and the outside: interoceptive sensitivity and social distances

Humans' ability to represent their body state from within through interoception has been proposed to predict different aspects of human cognition and behaviour. We focused on the possible contribution of interoceptive sensitivity to social behaviour as mediated by adaptive modulation of autonomic response. We, thus, investigated whether interoceptive sensitivity to one's heartbeat predicts participants' autonomic response at different social distances. We measured respiratory sinus arrhythmia (RSA) during either a Social or a Non-social task. In the Social task each participant viewed an experimenter performing a caress-like movement at different distances from their hand. In the Non-social task a metal stick was moved at the same distances from the participant's hand. We found a positive association between interoceptive sensitivity and autonomic response only for the social setting. Moreover, only good heartbeat perceivers showed higher autonomic response 1) in the social compared to the non-social setting, 2) specifically, when the experimenter's hand was moving at boundary of their peripersonal space (20 cm from the participant's hand). Our findings suggest that interoceptive sensitivity might contribute to interindividual differences concerning social attitudes and interpersonal space representation via recruitment of different adaptive autonomic response strategies.

Emotional regulation and bodily sensation: interoceptive awareness is intact in borderline personality disorder

Emotional dysregulation is a core component of borderline personality disorder (BPD). Theoretical models suggest that deficits in labeling physiological sensations of emotion contribute to affective instability in BPD. Interoceptive awareness refers to the ability to perceive changes in internal bodily states, and is linked to the subjective experience and control of emotions. The authors tested whether differences in interoceptive awareness accounted for emotional instability in BPD. Patients diagnosed with BPD (n = 24) were compared to healthy controls (n = 30) on two established measures of interoceptive awareness, a heartbeat perception task and a heartbeat monitoring task. Contrary to their hypothesis, the authors observed no significant differences in objective measures of interoceptive awareness. Their findings provide strong evidence against the notion that difficulties in emotional regulation in BPD are connected to differences in interoceptive awareness.

Enhanced cardiac perception is associated with increased susceptibility to framing effects

Previous studies suggest in line with dual process models that interoceptive skills affect controlled decisions via automatic or implicit processing. The "framing effect" is considered to capture implicit effects of task-irrelevant emotional stimuli on decision-making. We hypothesized that cardiac awareness, as a measure of interoceptive skills, is positively associated with susceptibility to the framing effect. Forty volunteers performed a risky-choice framing task in which the effect of loss versus gain frames on decisions based on identical information was assessed. The results show a positive association between cardiac awareness and the framing effect, accounting for 24% of the variance in the framing effect. These findings demonstrate that good interoceptive skills are linked to poorer performance in risky choices based on ambivalent information when implicit bias is induced by task-irrelevant emotional information. These findings support a dual process perspective on decision-making and suggest that interoceptive skills mediate effects of implicit bias on decisions.

Interoceptive Awareness as a Moderator of Affective Responses to Social Exclusion

Previous research has yielded inconsistent results concerning affective reactions to social exclusion. The present study provides evidence that conscious perception of bodily signals (“interoceptive awareness”) constitutes an important moderating factor in this context. We compared participants with high versus low cardiac interoceptive awareness in regard to affective, cognitive, and physiological measures while they were included and excluded in a discussion with confederates. Participants with high interoceptive awareness showed a smaller decrease of positive affect and perceived acceptance as well as a smaller increase of negative affect and perceived rejection when comparing an inclusion phase with a subsequent exclusion phase than did participants with low interoceptive awareness. No significant differences in cognitive and physiological measures were observed. We assume that individuals with high interoceptive awareness, to whom physiological signals are more easily accessible, reduce aversive states to a larger degree by using somatic information for self-regulation.

Through the eyes of anxiety: Dissecting threat bias via emotional-binocular rivalry

An extensive body of research has demonstrated that anxious individuals abnormally process threat-related content. Yet, the manner in which clinical anxiety affects the selection of threatening signals and their maintenance within consciousness is yet to be explored. The present study used an emotional binocular rivalry (e-BR) procedure, in which pictures of faces depicting either fearful or neutral expressions competed with pictures of a house for conscious perception. We assumed that first- or cumulative-preferred perception of faces with fearful over neutral expression (i.e., initial or sustained threat bias, respectively) stand for preferential selection or maintenance of fear content in awareness, correspondingly. Unmedicated patients with social anxiety disorder (SAD) and panic disorder (PAD) were compared to healthy controls for threat-related perceptual biases in the e-BR. At first perception of face, both SAD and PAD patients showed a greater initial threat bias than healthy controls. In contrast, at cumulative dwell-time of face, patient groups demonstrated a diminished sustained threat bias relative to healthy controls, yet in a different manner. SAD patients showed a sustained threat bias, though it was smaller than in healthy controls. Furthermore, increased levels of reported anxiety among SAD patients were associated with enhanced sustained perception of neutral faces. PAD patients, on the other hand, showed no sustained threat bias and a diminished cumulative perception of fearful faces with increased levels of anxiety traits. These findings indicate that anxiety disorders commonly involve an initially enhanced selection of threat signals into awareness, followed by disorder-specific manifestation of diminished preferred maintenance of threat in awareness.

An animal model of panic vulnerability with chronic disinhibition of the dorsomedial/perifornical hypothalamus

Panic disorder (PD) is a severe anxiety disorder characterized by susceptibility to induction of panic attacks by subthreshold interoceptive stimuli such as sodium lactate infusions or hypercapnia induction. Here we review a model of panic vulnerability in rats involving chronic inhibition of GABAergic tone in the dorsomedial/perifornical hypothalamic (DMH/PeF) region that produces enhanced anxiety and freezing responses in fearful situations, as well as a vulnerability to displaying acute panic-like increases in cardioexcitation, respiration activity and "flight" associated behavior following subthreshold interoceptive stimuli that do not elicit panic responses in control rats. This model of panic vulnerability was developed over 15 years ago and has provided an excellent preclinical model with robust face, predictive and construct validity. The model recapitulates many of the phenotypic features of panic attacks associated with human panic disorder (face validity) including greater sensitivity to panicogenic stimuli demonstrated by sudden onset of anxiety and autonomic activation following an administration of a sub-threshold (i.e., do not usually induce panic in healthy subjects) stimulus such as sodium lactate, CO(2), or yohimbine. The construct validity is supported by several key findings; DMH/PeF neurons regulate behavioral and autonomic components of a normal adaptive panic response, as well as being implicated in eliciting panic-like responses in humans. Additionally, patients with PD have deficits in central GABA activity and pharmacological restoration of central GABA activity prevents panic attacks, consistent with this model. The model's predictive validity is demonstrated by not only showing panic responses to several panic-inducing agents that elicit panic in patients with PD, but also by the positive therapeutic responses to clinically used agents such as alprazolam and antidepressants that attenuate panic attacks in patients. More importantly, this model has been utilized to discover novel drugs such as group II metabotropic glutamate agonists and a new class of translocator protein enhancers of GABA, both of which subsequently showed anti-panic properties in clinical trials. All of these data suggest that this preparation provides a strong preclinical model of some forms of human panic disorders.

Toward a cognitive view of trait mindfulness: distinct cognitive skills predict its observing and nonreactivity facets

Dispositional variations in mindfulness and its facets have garnered considerable recent interest in the clinical and personality literatures. Theoretically, high mindful individuals have been characterized as more attuned to momentary sensations and perceptions and/or better able to execute behavior in a controlled manner, yet data of this relatively cognitive type have not been reported. In addition, perceptual attunement and executive control are distinct skills that may underlie, or at least correlate with, distinct facets of mindfulness. In 3 studies involving college students (N = 297), support for the latter idea was found. Individuals high in the observing (but not nonreactivity) facet of mindfulness demonstrated superior perceptual abilities in visual working memory (Study 1) and temporal order (Study 2) tasks. On the other hand, individuals high in the nonreactivity (but not observing) facet of mindfulness exhibited greater cognitive control flexibility (Study 3). Implications for understanding the cognitive basis of mindfulness facets are discussed.

Altered auditory processing in patients with panic disorder: a pilot study

OBJECTIVES

Clinical and electrophysiological studies suggest that panic disorder (PD) patients show disturbed response inhibition to sensory stimuli. Thus, habituation of neuronal activation after repeated sine tone stimulation was assessed by functional magnetic resonance imaging (fMRI) in patients with PD.

METHODS

Twenty patients with PD and 20 age- and gender-matched healthy controls were assessed by 3T fMRI for auditory habituation. During three stimulation cycles of digitally generated pulsed (ν=5 Hz) 800-Hz sine tones alternating with silent periods, activation of the auditory cortex and other anxiety- or sensory integration-related regions was assessed. Brain activation was further analyzed dependent on functional serotonin transporter (5-HTT) gene variation (5-HTTLPR).

RESULTS

PD patients demonstrated an extended brain activity in the first stimulation block, which normalized during the second stimulation cycle. A positive correlation with anxiety measures (HAMA) and an increased activity of distinct anxiety- or sensory integration-related areas (e.g., BA 22, BA 10) were seen during the third block of auditory stimulation. There was a significant interaction of left amygdala activation and the 5-HTTLPR S allele.

CONCLUSIONS

Our results support the hypothesis of an aberrant processing of sensory information in PD patients. This phenomenon may underlie an enhanced responsiveness to anxiety-relevant or irrelevant stimuli possibly increasing PD vulnerability.

Heartbeat perception in social anxiety before and during speech anticipation

According to current cognitive models of social phobia, individuals with social anxiety create a distorted image of themselves in social situations, relying, at least partially, on interoceptive cues. We investigated differences in heartbeat perception as a proxy of interoception in 48 individuals high and low in social anxiety at baseline and while anticipating a public speech. Results revealed lower error scores for high fearful participants both at baseline and during speech anticipation. Speech anticipation improved heartbeat perception in both groups only marginally. Eight of nine accurate perceivers as determined using a criterion of maximum difference between actual and counted beats were high socially anxious. Higher interoceptive accuracy might increase the risk of misinterpreting physical symptoms as visible signs of anxiety which then trigger negative evaluation by others. Treatment should take into account that in socially anxious individuals perceived physical arousal is likely to be accurate rather than false alarm.

What is an anxiety disorder?

Initiated as part of the ongoing deliberation about the nosological structure of DSM, this review aims to evaluate whether the anxiety disorders share features of responding that define them and make them distinct from depressive disorders, and/or that differentiate fear disorders from anxious-misery disorders. The review covers symptom self-report as well as on-line indices of behavioral, physiological, cognitive, and neural responding in the presence of aversive stimuli. The data indicate that the anxiety disorders share self-reported symptoms of anxiety and fear; heightened anxiety and fear responding to cues that signal threat, cues that signal no threat, cues that formerly signaled threat, and contexts associated with threat; elevated stress reactivity to aversive stimuli; attentional biases to threat-relevant stimuli and threat-based appraisals of ambiguous stimuli; and elevated amygdala responses to threat-relevant stimuli. Some differences exist among anxiety disorders, and between anxiety disorders and depressive disorders. However, the differences are not fully consistent with proposed subdivisions of fear disorders vs. anxious misery disorders, and comparative data in large part are lacking. Given the high rates of co-morbidity, advances in our understanding of the features of responding that are shared across vs. unique to anxiety and depressive disorders will require dimensional approaches. In summary, the extant data help to define the features of responding that are shared across anxiety disorders, but are insufficient to justify revisions to the DSM nosology at this time.

Interoceptive sensitivity in anxiety and anxiety disorders: an overview and integration of neurobiological findings

Interoceptive sensitivity, particularly regarding heartbeat, has been suggested to play a pivotal role in the pathogenesis of anxiety and anxiety disorders. This review provides an overview of methods which are frequently used to assess heartbeat perception in clinical studies and summarizes presently available results referring to interoceptive sensitivity with respect to heartbeat in anxiety-related traits (anxiety sensitivity, state/trait anxiety), panic disorder and other anxiety disorders. In addition, recent neurobiological studies of neuronal activation correlates of heartbeat perception using positron emission tomography (PET), functional magnetic resonance imaging (fMRI) or electroencephalographic (EEG) techniques are presented. Finally, possible clinical and therapeutic implications (e.g., beta-blockers, biofeedback therapy, cognitive interventions and interoceptive exposure) of the effects of heartbeat perception on anxiety and the anxiety disorders and the potential use of interoceptive sensitivity as an intermediate phenotype of anxiety disorders in future neurobiological and genetic studies are discussed.

Differential effects of anxiety and depression on interoceptive accuracy

BACKGROUND

Feedback from the body is assumed to be altered in depression. Nevertheless, empirical studies investigating this assumed relationship remain sparse. This study aimed to examine interrelations between the ability to perceive heartbeats accurately (interoceptive awareness), depressive symptoms, and anxiety in healthy participants.

METHODS

A well-validated heartbeat perception task to measure interoceptive awareness together with two questionnaires indexing anxiety and depression were administered to 119 participants.

RESULTS

As main results we observed a negative correlation between heartbeat perception and depression. Only when focussing on high anxiety levels this negative correlation coefficient between depression and interoception remained significant.

CONCLUSIONS

Our results highlight the possible relationship between depressive symptoms and interoceptive awareness and may have further implications for theoretical models of anxiety disorders and their treatment. Further research is required to examine the potential consequences of altering interoceptive awareness in healthy subjects in relation to depression and anxiety.

Cardiac modulation of startle eye blink

As an alternative to interoceptive paradigms that depend on the participants' active cooperation, two studies are presented to show that startle methodology may be employed to study visceral afferent processing. The first study of 38 volunteers showed that startle responses were smaller when elicited during cardiac systole as compared to diastole. In the second study, 31 diabetic patients were divided into two groups, having normal or diminished (<6 ms/mmHg) baroreflex sensitivity (BRS). Patients with normal BRS showed the same results found in healthy volunteers. Diabetic patients with diminished BRS did not show this pattern. Because diminished BRS is an indicator of impaired baro-afferent signal transmission, it is concluded that cardiac modulation of startle is associated with intact baro-afferent feedback. Thus, pre-attentive startle methodology is feasible to study visceral afferent processing originating from the cardiovascular system.

Muscle tension in generalized anxiety disorder: a critical review of the literature

BACKGROUND

Generalized anxiety disorder (GAD) is a prevalent, disabling, and often chronic disorder. With a typical recovery rate of only about 40% with current psychological treatments a better understanding of potential psychophysiological mechanisms is vital.

METHODS

Since the most discriminative somatic symptom of GAD compared to other anxiety disorders is muscle tension this review qualitatively examines the literature on muscle tension as it relates to GAD and muscle relaxation therapy for GAD patients.

RESULTS

Muscle tension in GAD is poorly understood. Experimental studies refute the often-assumed direct relationship between anxiety and muscle tension. However, muscle relaxation therapies have been as effective as cognitive interventions directly addressing the defining symptom worry.

CONCLUSIONS

Muscle tension in its objective and subjective representations may play a role in GAD through various pathways that are testable. Future research needs to better examine the different aspects and functions of muscle tension in GAD.

The Relationship Between Pain Perception and Interoception

The question of whether the perception of externally applied pain stimuli and the perception of interoceptive stimuli are based upon similar neuronal or behavioral processes is still open to debate. If such a similarity exists, one would expect that persons who are highly sensitive to visceral stimuli would also exhibit a higher sensitivity to pain stimuli. The present study investigated the sensitivity to heat pain of individuals with high vs. low cardiac interoceptive sensitivity. Pain threshold and pain tolerance were assessed using a testing-the-limits procedure. Furthermore, participants rated the subjective intensity and unpleasantness of tonic heat stimuli on visual analog scales and in a questionnaire. The results show that pain experience did not differ between participants with high and low interoceptive sensitivity, nor did correlation analyses reveal significant relationships between pain experience and cardiac interoceptive sensitivity. These findings suggest that the pathway of peripheral pain processing is at least partially independent of the pathway of interoceptive sensations.

Reduced perception of bodily signals in anorexia nervosa

OBJECTIVE

Interoceptive awareness is known to be impaired in eating disorders. To date, it has remained unclear whether this variable is related to the construct of interoceptive sensitivity. Interoceptive sensitivity is considered to be an essential variable in emotional processes. The objective of the study was to elucidate this potential relationship and to clarify whether general interoceptive sensitivity is reduced in anorexia nervosa.

METHODS

Using a heartbeat perception task, interoceptive sensitivity was assessed in 28 female patients with anorexia nervosa and 28 matched healthy controls. Questionnaires assessing interoceptive awareness (EDI) and several other variables were also administered.

RESULTS

Patients with anorexia nervosa displayed significantly decreased interoceptive sensitivity. They also had more difficulties in interoceptive awareness.

CONCLUSIONS

In addition to a decreased ability to recognize certain visceral sensations related to hunger, there is a generally reduced capacity to accurately perceive bodily signals in anorexia nervosa. This highlights the potential importance of interoceptive sensitivity in the pathogenesis of eating disorders.

Neural pathways underlying lactate-induced panic

Panic disorder is a severe anxiety disorder characterized by susceptibility to induction of panic attacks by subthreshold interoceptive stimuli such as 0.5 M sodium lactate infusions. Although studied for four decades, the mechanism of lactate sensitivity in panic disorder has not been understood. The dorsomedial hypothalamus/perifornical region (DMH/PeF) coordinates rapid mobilization of behavioral, autonomic, respiratory and endocrine responses to stress, and rats with disrupted GABA inhibition in the DMH/PeF exhibit panic-like responses to lactate, similar to panic disorder patients. Utilizing a variety of anatomical and pharmacological methods, we provide evidence that lactate, via osmosensitive periventricular pathways, activates neurons in the compromised DMH/PeF, which relays this signal to forebrain limbic structures such as the bed nucleus of the stria terminalis to mediate anxiety responses, and specific brainstem sympathetic and parasympathetic pathways to mediate the respiratory and cardiovascular components of the panic-like response. Acutely restoring local GABAergic tone in the DMH/PeF blocked lactate-induced panic-like responses. Autonomic panic-like responses appear to be a result of DMH/PeF-mediated mobilization of sympathetic responses (verified with atenolol) and resetting of the parasympathetically mediated baroreflex. Based on our findings, DMH/PeF efferent targets such as the C1 adrenergic neurons, paraventricular hypothalamus, and the central amygdala are implicated in sympathetic mobilization; the nucleus of the solitary tract is implicated in baroreflex resetting; and the parabrachial nucleus is implicated in respiratory responses. These results elucidate neural circuits underlying lactate-induced panic-like responses and the involvement of both sympathetic and parasympathetic systems.

The assessment of present-moment awareness and acceptance: the Philadelphia Mindfulness Scale

The purpose of this project was to develop a bidimensional measure of mindfulness to assess its two key components: present-moment awareness and acceptance. The development and psychometric validation of the Philadelphia Mindfulness Scale is described, and data are reported from expert raters, two nonclinical samples (n = 204 and 559), and three clinical samples including mixed psychiatric outpatients (n = 52), eating disorder inpatients (n = 30), and student counseling center outpatients (n = 78). Exploratory and confirmatory factor analyses support a two-factor solution, corresponding to the two constituent components of the construct. Good internal consistency was demonstrated, and relationships with other constructs were largely as expected. As predicted, significant differences were found between the nonclinical and clinical samples in levels of awareness and acceptance. The awareness and acceptance subscales were not correlated, suggesting that these two constructs can be examined independently. Potential theoretical and applied uses of the measure are discussed.

Interozeptive Sensitivität, Gefühle und Verhaltensregulation

Die zentralnervöse Verarbeitung afferenter Signale aus dem Körperinneren ist nicht nur bei der basalen Kontrolle homöostatischer Prozesse im Körper zur Regulation fundamentaler Adaptationsprozesse des Organismus relevant, sondern spielt zusammen mit der bewussten Perzeptionsgenauigkeit dieser körperlichen Signale („interozeptive Sensitivität“) auch bei der Regulation komplexer kognitiver, emotionaler und behavioraler Prozesse eine nicht zu unterschätzende Rolle. Diese Übersichtsarbeit stellt theoretische Grundlagen zur interozeptiven Sensitivität dar und gibt einen Überblick über aktuelle empirische Forschungsergebnisse.

Heartbeat perception in depression

Alterations in bodily awareness have been implicated in depression but there has been little detailed empirical characterisation of the degree and accuracy of body perception in the disorder. The present study examined the objective accuracy of heartbeat perception (using the Schandry mental tracking task) and the subjective degree of bodily focus (using the Bodily Consciousness Questionnaire; BCQ) in healthy control volunteers, a moderately depressed community sample, and a more severely depressed clinic sample (n=18 in each group). The community sample showed less accurate heartbeat perception than the control group as expected. Counter to prediction, however, the more severely depressed clinic sample performed better than the community depressed sample and equivalently to control volunteers on the Schandry task. There were no group differences on subjective bodily awareness. Implications for theories of depression are discussed.

Interoceptive sensitivity and physical effort: Implications for the self-control of physical load in everyday life

This study examined the relationship between interoceptive sensitivity and the behavioral self-regulation of physical load. According to their performance in a heartbeat detection task, 34 participants were classified as good or poor heartbeat perceivers. Participants pedaled on a bicycle ergometer for 15 min and were free to choose the tempo of their cycling. Good heartbeat perceivers covered a significantly shorter distance and showed a significantly smaller increase in mean heart rate, stroke volume, and cardiac output. There were significant negative correlations between heartbeat perception score and covered distance, changes in heart rate, changes in stroke volume, and changes in cardiac output. These results were not explained by differences in physical fitness level (PWC150). The findings suggest that good heartbeat perceivers show a more finely tuned behavioral self-regulation of physical load than poor heartbeat perceivers.

Discomfort intolerance: Development of a construct and measure relevant to panic disorder

The construct of discomfort intolerance (proposed as an individual difference in the ability to tolerate uncomfortable sensations) is introduced and psychometric properties of a measure of this trait are provided. The Discomfort Intolerance Scale (DIS), a self-report measure of discomfort intolerance, was evaluated using a variety of samples (total N approximately 1700), including patients with panic disorder, clinical controls, and nonclinical community members. Factor analyses suggest the DIS contains two factors, including a factor indexing the ability to tolerate discomfort and pain (Factor 1: alpha = .91), and a factor, which appears to measure avoidance of physical discomfort (Factor 2: alpha = .72). Cross-time reliability shows good stability across 12 weeks (Factor 1 = .63, Factor 2 = .66). Convergent and discriminant validity coefficients indicated that the DIS performed as expected against established measures of psychopathology. The DIS appears to be a sound measure of a broad individual difference variable tapping the ability to tolerate a variety of uncomfortable sensations and may be relevant to the pathogenesis of anxiety disorders.

Are Current Theories of Panic Falsifiable?

The authors examine 6 theories of panic attacks as to whether empirical approaches are capable of falsifying them and their heuristic value. The authors conclude that the catastrophic cognitions theory is least falsifiable because of the elusive nature of thoughts but that it has greatly stimulated research and therapy. The vicious circle theory is falsifiable only if the frightening internal sensations are specified. The 3-alarms theory postulates an indeterminate classification of attacks. Hyperventilation theory has been falsified. The suffocation false alarm theory lacks biological parameters that unambiguously index dyspnea or its distinction between anticipatory and panic anxiety. Some correspondences postulated between clinical phenomena and brain areas by the neuroanatomical hypothesis may be falsifiable if panic does not depend on specific thoughts. All these theories have heuristic value, and their unfalsifiable aspects are capable of modification.

Heartbeat sensitivity in adults with congenital heart disease

This study tested the hypothesis that patients with a congenital heart disease are sensitive regarding heartbeat perception, reflected in enhanced attention for heartbeat, estimation of own heart rate, and a vulnerability to become anxious by listening to heartbeat sounds. Twenty adults with a congenital heart disease, and 20 healthy controls conducted 3 experimental tasks: a concentration task during distraction by heartbeat sounds, own heart rate estimation, and exposure to different patterns of heartbeat sounds. The results showed that patients were more distracted by heartbeat, and were also worse at estimating heart rate than controls. However, heartbeat sounds did not evoke anxiety. In conclusion, patients with a congenital heart disease may differ from controls in heartbeat perception, but there was no support for obsessive monitoring for heartbeat or excessive reactions to heartbeat sounds.

Heart-beat perception, panic/somatic symptoms and anxiety sensitivity in children

There is considerable evidence implicating heart-beat perception (HBP) accuracy and anxiety sensitivity (AS) in the development of panic in adults. However, to date there have been no studies exploring the association between HBP, AS and childhood panic/somatic symptoms. Seventy-nine children aged 8 to 11 years completed a mental tracking paradigm (Psychophysiology 18 (1981) 483) to assess HBP, the Children's Anxiety Sensitivity Index (J Clin Chil Psychol 20 (1991) 162) and the Screen for Childhood Anxiety Related Emotional Disorders (J Am Acad Child Adoles Psych 38 (1999) 1230). Those with good HBP (n = 7, 9%) had significantly higher panic/somatic symptoms (t = -1.71, P < 0.05), and AS (t = -2.16, P < 0.02) than those with poor HBP. There were no effects of age, sex or BMI on HBP. Those with high levels of panic/somatic symptoms were seven times more likely to have good HBP and had AS scores 1 S.D. higher than the remainder of the sample. Multivariate analyses revealed that these two phenotypes had independent associations with high panic/somatic symptoms. These results extend the literature on HBP and panic and suggest that in children, as in adults, increased panic/somatic symptoms are associated with enhanced ability to perceive internal physiological cues, and fear of such sensations.

Neural systems supporting interoceptive awareness

Influential theories of human emotion argue that subjective feeling states involve representation of bodily responses elicited by emotional events. Within this framework, individual differences in intensity of emotional experience reflect variation in sensitivity to internal bodily responses. We measured regional brain activity by functional magnetic resonance imaging (fMRI) during an interoceptive task wherein subjects judged the timing of their own heartbeats. We observed enhanced activity in insula, somatomotor and cingulate cortices. In right anterior insular/opercular cortex, neural activity predicted subjects' accuracy in the heartbeat detection task. Furthermore, local gray matter volume in the same region correlated with both interoceptive accuracy and subjective ratings of visceral awareness. Indices of negative emotional experience correlated with interoceptive accuracy across subjects. These findings indicate that right anterior insula supports a representation of visceral responses accessible to awareness, providing a substrate for subjective feeling states.

Catastrophic thinking about pain increases discomfort during internal atrial cardioversion

OBJECTIVES

This study investigated whether pain catastrophizing is associated with distress and perceived disability in patients with atrial fibrillation, whether pain catastrophizing predicts pain and fear during a medical procedure of atrial cardioversion, and whether pain catastrophizing influences the effects of an opioid analgesic during internal cardioversion.

METHODS

A secondary analysis is performed upon data from a double-blind placebo-controlled trial during which the effect of intranasal butorphanol tartrate (INB) was evaluated in patients with atrial fibrillation using a step-up internal atrial cardioversion protocol. Before the procedure, patients completed measures of pain catastrophizing, mood, distress and perceived disability. After each shock, patients completed measures of pain and fear.

RESULTS

We found that pain catastrophizing predicted the affective pain rating of the first shock, and the fear increase during subsequent shocks. There was no effect of INB. However, when controlling for the differences in pain catastrophizing, INB significantly reduced fear as compared to placebo. This suggests that the effects of INB during atrial cardioversion were overshadowed by the effects of pain catastrophizing.

CONCLUSIONS

It is recommended that in future atrial cardioversion trials, stratification based on pain catastrophizing be performed. Reducing catastrophizing thinking about pain through cognitive-behavioral techniques are likely to reduce levels of fear during internal atrial cardioversion and may increase the effectiveness of concomitant analgesics.

A twin study of anxiety-related behaviours in pre-school children

BACKGROUND

From middle childhood onwards, substantial evidence points to phenotypic differentiation between anxiety diagnostic categories such as generalised anxiety, separation anxiety, specific phobia, and obsessive-compulsive disorders. However, little is known about the genetics of these categories and especially about the phenotypic and genetic structure of related behaviours in pre-school children.

METHODS

We examined the phenotypic differentiation and genetics of mother-reported anxiety-related behaviours in 4,564 four-year-old twin pairs, from a population-based sample.

RESULTS

Confirmatory factor analyses provided support for five correlated factors: General Distress, Separation Anxiety, Fears, Obsessive-Compulsive Behaviours, and Shyness/Inhibition. Genetic influences were found on all five factors, but the pattern of influences differed considerably across them, with particularly high heritability estimates for Obsessive-Compulsive Behaviours and Shyness/Inhibition, and substantial shared environmental influence on Separation Anxiety. Multivariate genetic analyses revealed moderate genetic correlations between the five factors. Genetic overlap was particularly pronounced between General Distress and the other anxiety-related behaviours, accounting for about half of their covariance. Genetic variance on Obsessive-Compulsive Behaviours was the least correlated with the other scales. The shared environmental influences correlated highly across the factors, accounting for the greatest proportion of covariation between Separation Anxiety, Fears and Obsessive-Compulsive Behaviours. The non-shared environment influences were largely variable specific.

CONCLUSIONS

These data provide evidence for phenotypic and genetic overlap as well as differentiation between aspects of anxiety-related behaviours in young children. We conclude that research with young children will benefit from more specific assessments of anxiety-related behaviours in addition to less differentiated assessments of 'internalising' symptoms.