Exaggerated perception of normal physiological responses to stress and hypercapnia in young women with numerous functional somatic symptoms

Druggable Targets and Compounds with Both Antinociceptive and Antipruritic Effects

Pain and itch are both important manifestations of various disorders, such as herpes zoster, atopic dermatitis, and psoriasis. Growing evidence suggests that both sensations have shared mediators, overlapping neural circuitry, and similarities in sensitization processes. In fact, pain and itch coexist in some disorders. Determining pharmaceutical agents and targets for treating pain and itch concurrently is of scientific and clinical relevance. Here we review the neurobiology of pain and itch and discuss the pharmaceutical targets as well as novel compounds effective for the concurrent treatment of these sensations.

Perceptual and Ventilatory Responses to Hypercapnia in Athletes and Sedentary Individuals

Purpose

Hypercapnic chemosensitivity traditionally captures the ventilatory response to elevated pressures of carbon dioxide in the blood. However, hypercapnia also contributes to subjective breathing perceptions, and previously we demonstrated a closer matching of perception to changes in ventilation in athletes compared to controls. Here we investigated any potential underlying hypercapnic chemosensitivity differences between groups, and explored whether these measures relate to ventilatory and perceptual responses during exercise as well as trait levels of affect.

Methods

A hypercapnic challenge, incremental maximal exercise test and affective questionnaires were completed by 20 endurance athletes and 20 age-/sex-matched sedentary controls. The hypercapnic challenge involved elevating end-tidal PCO₂ by 0.8% (6.1 mmHg) and 1.5% (11.2 mmHg) for 3 min each (randomised), with constant end-tidal oxygen. Ventilatory and perceptual responses to hypercapnia were compared between groups, and within each group the relationships between hypercapnic chemosensitivity (slope analyses) and exercising ventilation and perceptions were calculated using Spearman’s non-parametric correlations.

Results

While absolute ventilation differences during hypercapnia and exercise were observed, no group differences were found across hypercapnic chemosensitivity (slope) measures. Correlation analyses revealed the anxiety hypercapnic response was related to maximal exercise anxiety, but only in sedentary individuals.

Conclusion

Ventilatory and perceptual hypercapnic chemosensitivity do not differ between athletes and sedentary individuals. However, ventilatory and anxiety hypercapnic chemosensitivities were related to ventilatory and anxiety responses during exercise in untrained individuals only. Athletes may employ additional strategies during exercise to reduce the influence of chemosensitivity on ventilatory and perceptual responses.

Distinctive body perception mechanisms in high versus low symptom reporters: A neurophysiological model for medically-unexplained symptoms

OBJECTIVE

The neurophysiological processes involved in the generation of medically-unexplained symptoms (MUS) remain unclear. This study tested three assumptions of the perception-filter model contributing to MUS: (I.) increased bodily signal strength (II.) decreased filter function, (III.) increased perception.

METHODS

In this cross-sectional, observational study, trait MUS were assessed by a web-based survey (N = 486). The upper and lower decile were identified as extreme groups of high (HSR; n = 29; 26 women; Mage = 26.0 years) and low symptom reporters (LSR; n = 29; 21 women; Mage = 28.4 years). Mean heart rate (HR) and heart rate variability (HRV), and cortisol awakening response (CAR) were assessed as indicators of bodily signal strength (I.). Heartbeat-evoked potentials (HEPs) were assessed during rest and a heartbeat perception task. HEPs reflect attentional resources allocated towards heartbeats and served as index of filter function (II.). Interoceptive accuracy (IAc) in heartbeat perception was assessed as an indicator of perception (III.).

RESULTS

HSR showed higher HR and lower HRV (RMSSD) than LSR (I.), but no differences in CAR. HSR exhibited a stronger increase of HEPs when attention was focused on heartbeats than LSR (II.); there were no group differences in IAc (III.).

CONCLUSIONS

The perception-filter model was partially confirmed in that HSR showed altered bodily signals suggesting higher sympathetic activity (I.); higher HEP increases indicated increased filter function for bodily signals (II.). As more attentional resources are mobilized to process heartbeats, but perception accuracy remains unchanged (III.), this overflow could be responsible for detecting minor bodily changes associated with MUS.

Altered Interoceptive Awareness in High Habitual Symptom Reporters and Patients With Somatoform Disorders

Objective: Altered interoception may play a major role in the etiology of medically unexplained symptoms (MUS). It remains unclear, however, if these alterations concern noticing of signals or if they are limited to the interpretation of signals. We investigated whether individuals with MUS differ in interoceptive awareness as assessed with the Multidimensional Assessment of Interoceptive Awareness (MAIA) questionnaire.

Methods: Study 1: A total of 486 individuals completed the Screening for Somatoform Disorders (SOMS-2). Thirty-two individuals each of the upper and lower decile of the SOMS distribution (low symptom reporters/LSR, high symptom reporters/HSR) completed the MAIA. Study 2: MAIA scores of individuals diagnosed with somatoform disorder (SFD; n = 26) were compared to individuals with major depressive disorder (MDD; n = 25) and healthy controls (HC; n = 26).

Results: HSR had lower scores than LSR on the MAIA scales Not-Distracting and Not-Worrying. The SFD and MDD groups showed lower scores than HC on the MAIA scales Not-Distracting, Self-Regulation, and Trusting. The MDD group scored lower than the other two groups on the scales Body Listening and Attention Regulation. There were no group differences on the scale Noticing.

Conclusion: HSR, SFD, and MDD patients do not differ from HC in the awareness of noticing of interoceptive signal processing, whereas cognitive facets of interoception, such as distraction or self-regulation are differentially affected. This highlights the necessity of including specifically targeted interventions, which improve interoceptive awareness, in the prevention and treatment of SFDs.

Evidence that subclinical somatoform dissociation is not characterised by heightened awareness of proprioceptive signals

INTRODUCTION

It has been suggested that abnormal perceptual processing and somatosensory amplification may be contributory factors to somatoform symptom reporting. A key source of somatosensory information is proprioception, yet the perception and integration of this sense has not been sufficiently investigated in those prone to somatoform disorders.

METHODS

Subclinical groups of high- and low-scorers on the Somatoform Dissociation Questionnaire made judgements about the location of their unseen hand following congruent or incongruent visuo-proprioceptive feedback, which was manipulated using a MIRAGE-mediated reality system.

RESULTS

No differences were found between groups, with both groups displaying normal proprioceptive accuracy under congruent conditions and equivalent visuo-proprioceptive integration under incongruent conditions.

CONCLUSIONS

The results suggest that amplification of, or abnormal weighting for, proprioceptive signals is not a contributing factor to somatoform symptom reporting.

Symptoms, the nature of fibromyalgia, and diagnostic and statistical manual 5 (DSM-5) defined mental illness in patients with rheumatoid arthritis and fibromyalgia

Purpose

To describe and evaluate somatic symptoms in patients with rheumatoid arthritis (RA) and fibromyalgia, determine the relation between somatization syndromes and fibromyalgia, and evaluate symptom data in light of the Diagnostic and Statistical Manual-5 (DSM-5) criteria for somatic symptom disorder.

Methods

We administered the Patient Health Questionnaire-15 (PHQ-15), a measure of somatic symptom severity to 6,233 persons with fibromyalgia, RA, and osteoarthritis. PHQ-15 scores of 5, 10, and 15 represent low, medium, and high somatic symptom severity cut-points. A likely somatization syndrome was diagnosed when PHQ-15 score was ≥10. The intensity of fibromyalgia diagnostic symptoms was measured by the polysymptomatic distress (PSD) scale.

Results

26.4% of RA patients and 88.9% with fibromyalgia had PHQ-15 scores ≥10 compared with 9.3% in the general population. With each step-wise increase in PHQ-15 category, more abnormal mental and physical health status scores were observed. RA patients satisfying fibromyalgia criteria increased from 1.2% in the PHQ-15 low category to 88.9% in the high category. The sensitivity and specificity of PHQ-15≥10 for fibromyalgia diagnosis was 80.9% and 80.0% (correctly classified = 80.3%) compared with 84.3% and 93.7% (correctly classified = 91.7%) for the PSD scale. 51.4% of fibromyalgia patients and 14.8% with RA had fatigue, sleep or cognitive problems that were severe, continuous, and life-disturbing; and almost all fibromyalgia patients had severe impairments of function and quality of life.

Conclusions

All patients with fibromyalgia will satisfy the DSM-5 “A” criterion for distressing somatic symptoms, and most would seem to satisfy DSM-5 “B” criterion because symptom impact is life-disturbing or associated with substantial impairment of function and quality of life. But the “B” designation requires special knowledge that symptoms are “disproportionate” or “excessive,” something that is uncertain and controversial. The reliability and validity of DSM-5 criteria in this population is likely to be low.

Inducing symptoms in high symptom reporters via emotional pictures: the interactive effects of valence and arousal

OBJECTIVE

Processing unpleasant emotional cues induces elevated reporting of physical symptoms, especially in people with high habitual symptom reporting. The present study examined the role of valence and arousal of emotional pictorial cues on this effect.

METHODS

Female participants (N=45; 21 high/24 low habitual symptom reporters) viewed six series of emotional pictures with a homogeneous affective content: low arousal/positive, high arousal/positive, low arousal/negative, high arousal/negative-disgust, high arousal/negative-threat and neutral. Heart rate (HR) and skin conductance level (SCL) were recorded during picture viewing and a symptom checklist and valence and arousal ratings were completed after each trial.

RESULTS

High habitual symptom reporters reported more symptoms than low habitual symptom reporters overall, but this difference was more pronounced when processing unpleasant high arousing cues. No group differences were found on physiological measures for any of the conditions, while perceived valence and arousal both moderated the relationship between habitual symptom reporting and symptom induction.

CONCLUSION

These findings show an interactive effect of unpleasantness and high arousal on elevated symptom reporting in high habitual symptom reporters, suggesting that different characteristics of emotional cues contribute to a somatic memory activation process leading to the experience of elevated symptoms.

Physiological reactivity to phobic stimuli in people with fear of flying

OBJECTIVE

The nature of the relationship between physiological and subjective responses in phobic subjects remains unclear. Phobics have been thought to be characterized by a heightened physiological response (physiological perspective) or by a heightened perception of a normal physiological response (psychological perspective).

METHOD

In this study, we examined subjective measures of anxiety, heart rate (HR), and cardiac autonomic responses to flight-related stimuli in 127 people who applied for fear-of-flying therapy at a specialized treatment center and in 36 controls without aviophobia.

RESULTS

In keeping with the psychological perspective, we found a large increase in subjective distress (eta(2)=.43) during exposure to flight-related stimuli in the phobics and no change in subjective distress in the controls, whereas the physiological responses of both groups were indiscriminate. However, in keeping with the physiological perspective, we found that, within the group of phobics, increases in subjective fear during exposure were moderately strong coupled to HR (r =.208, P=.022) and cardiac vagal (r =.199, P=.028) reactivity. In contrast to predictions by the psychological perspective, anxiety sensitivity did not modulate this coupling.

CONCLUSION

We conclude that subjective fear responses and autonomic responses are only loosely coupled during mildly threatening exposure to flight-related stimuli. More ecologically valid exposure to phobic stimuli may be needed to test the predictions from the physiological and psychological perspectives.

Dysfunction of stress responsive systems as a risk factor for functional somatic syndromes

The etiology of functional somatic syndromes or disorders (FSDs) is generally considered to be a multifactorial interplay between psychological, biological, and social factors. One of the most investigated biological factors is stress responsive system dysfunction. Despite more than twenty years of research of the autonomic nervous system and the hypothalamic-pituitary-adrenal axis, however, it is yet unknown whether dysfunctions in these systems play a causal role in the etiology of FSDs and whether they are generic or FSD-specific. In this review, we will give an overview of available evidence on whether or not alterations in these stress responsive systems can be considered causal risk factors of FSDs. We conclude that although not necessary factors for FSDs in general, lowered cardiac vagal activity and hypocortisolism may be pivotal in the etiology and treatment strategy in subgroups of subjects with a FSD. Such subgroups need to be better identified.

High symptom reporters are less interoceptively accurate in a symptom-related context

OBJECTIVE

We investigated the role of a symptom interpretation frame on the accuracy of interoception and on retrospective symptom reporting in nonclinical high and low reporters of medically unexplained symptoms.

METHODS

All participants (N=74) went through two subsequent trials of the Rebreathing Test, inducing altered respiration and other physical sensations as a result of a gradually increasing pCO(2) level in the blood. Each trial consisted of a baseline (60 s), a rebreathing phase (150 s), and a recovery phase (150 s). In one trial, the sensations were framed in a neutral way ("the gas mixture might alter breathing behavior and induce respiratory sensations"). In the other trial, a symptom frame was induced ("the gas mixture might alter breathing behavior and induce respiratory symptoms"). Breathing behavior was continuously monitored, subjective sensations were rated every 10 s, and after each trial, participants filled out a symptom checklist. Within-subject correlations between the subjective rating and its physiological referent were calculated for the rebreathing phase and recovery phase of each trial separately.

RESULTS

High symptom reporters had more (retrospective) complaints than low symptom reporters, especially in the symptom trial. Only in the symptom frame were high symptom reporters less accurate than low symptom reporters. The reduction in interoceptive accuracy (IA) in high symptom reporters was most striking in the recovery phase of the symptom frame trial.

CONCLUSION

A contextual cue, such as a reference to symptoms, reduced IA in high symptom reporters and this was more so during recovery from the symptom induction.

Generalized and symptom-specific sensitization of chronic itch and pain

BACKGROUND

Physicians are frequently confronted with patients reporting severe itch and pain. Particularly in patients suffering from persistent itch and pain, central and peripheral sensitization processes are assumed to be involved in the long-term maintenance and aggravation of the symptoms. The present study explores generalized and symptom-specific sensitization processes in patients suffering from persistent itch and pain. Specifically, it examines whether patients with chronic itch and pain are more sensitive to somatosensory stimuli (generalized sensitization) and simultaneously perceive somatosensory stimuli as a symptom of their main physical complaint, e.g. pain in chronic pain patients (symptom-specific sensitization).

METHODS

Thresholds for different mechanical and electrical sensory stimuli of Quantitative Sensory Testing were determined in 15 female patients suffering from chronic itch associated with atopic dermatitis, 15 female chronic pain patients diagnosed with fibromyalgia, and 19 female healthy controls. Intensities of itch and pain sensations were rated on a visual analogue scale.

RESULTS

As expected, the patient groups had significantly lower tolerance thresholds for the somatosensory stimuli applied than the healthy controls, supporting generalized sensitization. Moreover, patients with chronic itch consistently reported more itch, while patients with chronic pain partly reported more pain in response to analogous somatosensory stimuli than the healthy controls and the other patient group, indicating symptom-specific sensitization.

CONCLUSION

The present study provides preliminary support that both generalized and symptom-specific sensitization processes play a role in the regulation and processing of somatosensory stimulation of patients with chronic itch and pain.

Chemotherapy-induced nausea, vomiting, and fatigue--the role of individual differences related to sensory perception and autonomic reactivity

BACKGROUND

In spite of antiemetics, postchemotherapy side effects continue to be common and may affect compliance to cancer treatment. Among the known factors associated with increased symptom severity are: younger age, treatment toxicity, expected severity, and distress, but little is still known about the role of other factors. The aim of our study was to investigate the role of individual differences related to sensory perception for posttreatment side effects.

METHODS

Hundred and twenty-five women receiving adjuvant chemotherapy for breast cancer completed measures of absorption, autonomic perception, somatosensory amplification, trait anxiety, and expected severity at baseline. Pretreatment distress and posttreatment nausea, vomiting, and fatigue were assessed at the 1st, 4th, 6th and last cycles of chemotherapy.

RESULTS

While univariate analyses showed several factors to be associated with side effects, only absorption and pretreatment distress remained independent predictors of nausea and fatigue when controlling for the remaining factors. Posttreatment vomiting was only predicted by expected severity of vomiting.

CONCLUSION

Chemotherapy-induced side effects are related to increased autonomic nervous system activity, and absorption has been associated with increased autonomic nervous system reactivity to stress. The results suggest that individuals with high absorption may be at greater risk for developing side effects. Improved precision in identifying patients at risk of experiencing more severe side effects after cancer treatment will increase the ability to target treatments aimed at reducing these side effects.

Stress-induced muscle effort as a cause of repetitive strain injury?

The influence of stress-induced muscle effort during computer utilization was tested in patients with repetitive strain injury (RSI). Twenty academic researchers with a formal medical diagnosis of RSI and 20 matched controls, randomly selected from a sample of 71 colleagues with and without RSI, typed after stress (induced via an intelligence/skill task under social pressure) and after relaxation. Results indicated that both groups had more electromyography (EMG) activity in the shoulder muscles during typing after stress than after relaxation, but that patients started with higher baseline muscle activity. Furthermore, EMG activity of different muscle groups during typing after stress correlated among controls, but not among patients. Finally, analysis of intake forms showed that patients scored higher than controls on neuroticism and alexithymia, but not on extraversion, openness, agreeableness and conscientiousness. It was concluded that deviations in muscle activity during computer utilization, as well as neuroticism and alexithymia, may be risk factors for RSI.

Medically unexplained symptoms and between-group differences in 24-h ambulatory recording of stress physiology

People with medically unexplained symptoms (MUS) often have a comorbid history of stress and negative affect. Although the verbal-cognitive and (peripheral) physiological stress systems have shown a great degree of independence, at the same time it is claimed that chronic stress and negative affect can result in a disregulated physiological stress system, which may lead to MUS. Previous studies could not demonstrate a straightforward between subject relationship between MUS and stress physiology, supporting the view of independence. The aim of the current study was to further explore this relationship using an improved methodology based on ecologically valid 24-h real-life ambulatory recordings. Seventy-four participants (19 male; 55 female) with heterogeneous MUS were compared with 71 healthy controls (26 male; 45 females). Momentary experienced somatic complaints and mood, heart rate, cardiac autonomic activity, respiration and saliva cortisol were monitored using electronic diary and ambulatory registration devices. Participants with MUS reported much more momentary complaints and negative affect as compared to controls. Although MUS seemed to be associated with elevated heart rate and reduced low and very-low frequency heart period variability, these effects disappeared after controlling for differences in sports behaviour. No group differences were found for cardiac autonomic activity, respiration, end-tidal CO(2) and saliva cortisol. Our 24-h real-life ambulatory study did not support the existence of a connection between MUS and disregulated peripheral stress physiology. Future studies may instead focus on central measures to reveal potential abnormalities such as deviant central processing of visceral signals in MUS patients.

Explaining medically unexplained symptoms-models and mechanisms

We summarize the psychological mechanisms that have been linked to the development and maintenance of medically unexplained symptoms (MUS). Many models postulate that patients with MUS misinterpret physical sensations and show other cognitive abnormalities (e.g., an over-exclusive concept of health) that play a major role in symptom development. While there is strong evidence for the role of cognitive aspects, there is less evidence for their interaction with perceptual features (e.g., perceptual sensitivity, lowered perceptual threshold). Modern neuroimaging techniques show that the expectation of symptoms leads to the activation of brain areas corresponding to symptom perception, while distraction from symptoms reduces brain activity in perception areas. The frequently postulated monocausal organic attribution for physical sensations by patients with MUS needs to be modified, as many patients report multiple symptom attributions, including psychological. Symptom attributions and causal models depend on memorized concepts, and so memory processes need to be investigated in more detail. Aberrations in memory processes not only offer a link to understanding perceptual processes, but are also involved in doctor-patient interaction. This encounter is characterized by unsuccessful medical reassurance, which again involves memory processes. We conclude that psychological mechanisms such as expectation, distraction, and memory processes need to be integrated with biological models to aid understanding of MUS.

RSA fluctuation in major depressive disorder

Cardiac vagal control, as measured by indices of respiratory sinus arrhythmia (RSA), has been investigated as a marker of impaired self-regulation in mental disorders, including depression. Past work in depressed samples has focused on deficits in resting RSA levels, with mixed results. This study tested the hypothesis that depression involves abnormal RSA fluctuation. RSA was measured in depressed and healthy control participants during rest and during two reactivity tasks, each followed by a recovery period. Relative to controls, depressed persons exhibited lower resting RSA levels as well as less RSA fluctuation, primarily evidenced by a lack of task-related vagal suppression. Group differences in RSA fluctuation were not accounted for by differences in physical health or respiration, whereas group differences in resting RSA level did not survive covariate analyses. Depression may involve multiple deficits in cardiac vagal control.

Somatoform dissociation and somatosensory amplification are differentially associated with attention to the tactile modality following exposure to body-related stimuli

OBJECTIVE

Body-focused attention is regarded as an important maintaining factor for somatoform illness, although there is limited empirical evidence pertaining to this hypothesis. This study was conducted to assess whether individual differences in somatoform dissociation and somatosensory amplification were associated with biased attention towards the tactile modality, particularly following exposure to threatening body-related stimuli.

METHODS

Forty-eight nonclinical participants completed the Somatoform Dissociation Questionnaire (SDQ-20; a proxy measure of somatoform symptomatology), the Somatosensory Amplification Scale (SSAS), and a modality bias task. The task consisted of a series of body-relevant or body-irrelevant (scene) picture stimuli, half of which were threatening and half were neutral, followed by target stimuli in either the visual or the tactile modality. Participants judged the location of each target stimulus, and performance data were used to calculate the degree to which participants were biased towards the tactile modality following each of the picture types.

RESULTS

Participants in the high SDQ-20 group (defined by median split) showed a significant increase in tactile bias when responding to targets occurring 250 ms after the presentation of threatening body-relevant stimuli only. This effect was not observed for the low SDQ-20 group. Scores on the SSAS correlated negatively with tactile bias for both threatening and neutral body-relevant stimuli at 250 ms.

CONCLUSIONS

Individuals with a tendency to experience somatoform symptoms focus more on stimuli in the tactile modality immediately following exposure to threatening body-relevant information. In contrast, self-reported somatosensory amplification appears to be associated with attention away from the tactile modality rather than with increased tactile focus.

Anticipatory Nausea: The Role of Individual Differences Related to Sensory Perception and Autonomic Reactivity

BACKGROUND

Anticipatory nausea (AN) during chemotherapy has been difficult to control with conventional antiemetics. AN can lead cancer patients to delay or discontinue chemotherapy, possibly compromising the treatment.

PURPOSE

The aim is to investigate the possible influence on the development of AN of individual differences in absorption, somato-sensory amplification, and autonomic perception-measures theorized to be related to sensory perception and autonomic reactivity.

METHODS

Prior to treatment, 125 women (M age = 48.5 years) undergoing adjuvant chemotherapy for breast cancer rated their expected severity of side effects and completed the Tellegen Absorption Scale, the Somato-Sensory Amplification Scale, and the Autonomic Perception Questionnaire. AN, as well as anticipatory vomiting (AV), distress, and worry/anxiety, were measured prior to the fourth, sixth, and last cycle of chemotherapy. Posttreatment nausea (PN), vomiting, and fatigue were measured after the first, fourth, sixth, and last cycle.

RESULTS

34% of the women reported AN before 1 or more cycles. When controlling for treatment characteristics and other known predictors, AN was significantly associated with high absorption in addition to severity of PN, pretreatment worry/anxiety, and not receiving radiotherapy between chemotherapy sessions. AV was not associated with any of the variables investigated. Our data suggest that the association is strongest in the early phases of treatment.

CONCLUSIONS

Our results partly confirm the results of a previous study showing absorption and autonomic perception as predictors of anticipatory side effects in cancer patients receiving chemotherapy. Individuals high in absorption may be more autonomically reactive to aversive stimuli and, subsequently, more conditionable. Additional radiotherapy could be a competing stimulus, reducing the conditioning of chemotherapy-related nausea. Further studies investigating possible psycho-physiological mechanisms in the development of AN are needed.

Stress-induced heart symptoms and perceptual biases in patients with congenital heart disease

BACKGROUND

The aim of the present study is to clarify whether biased symptom perception towards heart symptoms may explain a reduced quality of life in patients with congenital heart disease (ConHD). The present study tested the hypothesis that the combination of ConHD and high trait anxiety increases the perception of heart symptoms during acute stress.

METHODS

25 patients and 24 healthy participants completed a stressful computer task. Participant's heart and non-heart symptoms were measured after stress and after relaxation. Heart rate, blood pressure, respiratory rate, and arterial partial pressure of CO2 were monitored continuously.

RESULTS

In line with the prediction, a combination of high trait anxiety and ConHD resulted in an increased perception of specifically heart symptoms during stress. Moreover, the increased perception of heart symptoms could not be explained by acute heart dysfunction.

CONCLUSIONS

Heart dysfunction is not the only cause of an increased perception of heart symptoms. A history of disease experience in combination with high trait anxiety may increase the perception of heart symptoms during stress and may eventually result in an increased risk of developing a reduced quality of life.

Rollercoaster asthma: when positive emotional stress interferes with dyspnea perception

The current study assessed how negative and positive stress is related to dyspnea perception. The participants were 25 young women with a medical diagnosis of severe asthma, and 15 matched controls. Stress was induced during repeated rollercoaster rides. Results showed that negative emotional stress and blood pressure peaked just before, and positive emotional stress and heart beat peaked immediately after rollercoaster rides. Dyspnea in women with asthma was higher just before than immediately after rollercoaster rides, even in women with asthma with a rollercoaster-evoked reduction in lung function. These results suggest that stressed and highly aroused individuals with chronic asthma tend to perceive dyspnea in terms of acquired, familiar associations between dyspnea and positive versus negative feeling states, favoring either underperception or overperception of dyspnea, depending on the emotional valence of a situation.

The relationship between specific anxiety syndromes and somatic symptoms in adolescents with asthma and other chronic diseases

BACKGROUND

The impact of a chronic disease on the emotional well-being of children and adolescents is controversial in the literature. This study tested the hypotheses that 1) a specific approach is required to assess emotional deviations in adolescents with chronic diseases and 2) specific anxiety symptoms are predictive of excessive somatic symptoms.

METHODS

Emotional and somatic symptoms were measured in four groups, selected from a community sample of 897 adolescents: 32 with asthma, 20 with other severe chronic diseases, 30 with median scores (the true comparison group), and 29 with minimal scores on common measures of trait anxiety and depression.

RESULTS

The asthma and chronic disease groups scored not significantly higher than the true comparison group on trait anxiety, depression, negative affectivity, five anxiety syndromes, anxiety-related physical, and miscellaneous somatic symptoms. The asthma and chronic disease groups scored only higher than the true comparison group on panic attacks and respiration symptoms. Regression analyses showed that severity of asthma was no significant factor, and the minimal group scored consistently lower than the other groups, except on physical injury fears. There were no group differences in positive affect. Girls scored higher than boys on specific anxiety syndromes (except on obsessive-compulsive disorder) and also on respiration symptoms.

CONCLUSION

Adolescents with severe chronic diseases deviated from a true comparison control group on panic attacks, but not on other negative and positive emotions.

Abnormal illness behaviour: physiological, psychological and social dimensions of coping with distress

PURPOSE OF REVIEW

Pilowsky introduced the term 'abnormal illness behaviour' to characterize syndromes of excessive or inadequate response to symptoms, including hypochondriasis, somatization, and denial of illness. This review summarizes recent work from sociology, health psychology and psychiatry that contributes to an understanding of the processes that may underlie abnormal illness behaviour.

RECENT FINDINGS

Disturbances in the regulation of physiological systems may account for many 'unexplained' symptoms and sickness behaviour. Increased attention to bodily sensations, sensitivity to pain and catastrophizing play important roles in illness behaviour in medical illness. Developmental adversities and parental modelling of illness behaviour in childhood may increase bodily preoccupation and health care utilization. Apparent cross-national differences in illness behaviour may reflect differences in health care systems, but cultural models of illness and social stigma remain important determinants of illness denial and avoidance of mental health services.

SUMMARY

Research into illness behaviour is relevant to efforts to rethink the psychiatric nosology of somatoform disorders. The discrete somatoform disorders might well be replaced by a dimensional framework that identifies specific pathological processes in cognition, perception and social behaviour that contribute to bodily distress, impaired coping, inappropriate use of health services, chronicity and disability.

Accuracy of respiratory symptom perception in different affective contexts

OBJECTIVE

The accuracy of respiratory symptom perception was investigated in different affective contexts in participants (N=48) scoring high or low for negative affectivity (NA).

METHODS

Within-subject correlations were calculated between two subjective ratings and their respective physiological referent (the rating of "deeper breathing" and respiratory volume, and rating of "faster breathing" and breathing frequency) across nine consecutive breathing trials. Three different air mixtures were used: room air, air enriched with 7.5% CO(2), and with 10% CO(2). For half the participants, the trials were framed in a pleasant context, created by adding a pleasant odour to the air mixture in addition to information announcing pleasant feelings as a result of breathing the air mixtures. The other half received the trials in a distressing context: A foul smelling odour was added and the information announced unpleasant feelings.

RESULTS

High-NA persons were overall less accurate than were low-NA persons in the perception of respiratory volume. For breathing frequency, high-NA persons were significantly less accurate in the distressing condition than in the pleasant one, whereas for low-NA persons, the information frame did not matter.

CONCLUSION

The study shows that the accuracy of respiratory symptom reports is reduced in high-NA persons, especially in a distressing context.

Negative affectivity and enhanced symptom reports: differentiating between symptoms in men and women

This study aimed to characterize individual bodily symptoms as regards their differential relationship with negative affectivity (NA). In a first step, 73 symptoms were rated by independent groups of raters (psychologists, medical doctors, healthy students) on the following characteristics: the extent to which a symptom (1) refers to a specific location in the body (vagueness), (2) may refer to both a physical condition and a negative emotional state (overlap), and (3) is likely to be a physiological manifestation of anxiety (anxiety). Each symptom was also rated on (4) the probability that it is caused by a clearly defined somatic pathology (somatic pathology), (5) how life-threatening or (6) compromising for the quality of life a symptom is, and (7) how worried one would be if the symptom were to be experienced in daily life (worrying). Two factors, severity and somatic versus psychic, explained 75% of the variance in the ratings on the symptom characteristics. Next, based on the data of 1017 university students (858 women), correlations of each individual symptom with NA were calculated for each gender. The pattern of correlation was highly variable and differed in important ways for men and women. Whereas the correlation of an individual symptom with NA could be predicted by both symptom factors in women (R(2)=52%), only the somatic versus psychic factor was a significant predictor in men (R(2)=11%). These results suggest that (1) NA should not be considered a general complaining factor, and (2) important gender differences exist regarding the type of symptoms that relate most strongly to NA.