The latent structure of anxiety symptoms in anxiety disorders

Panic symptom clusters differentially predict suicide ideation and attempt

Increasingly strong evidence links anxiety disorders in general and panic attacks in particular to suicidality. The underlying causes and specifics of this relation, however, remain unclear. The present article sought to begin addressing this question by clarifying the association between panic symptoms and suicidality. Data were sampled from the NESARC epidemiological data set from the US and analyzed as four independently, randomly selected subsets of 1000 individuals using structural equation modeling analyses and replicating results across samples. Evidence is presented for four symptom clusters (cognitive symptoms, respiratory distress, symptoms of alpha and beta adrenergic activation) and the differential association of each with suicidal ideation and attempts. Symptoms of alpha adrenergic activation predicted prior suicide attempt whereas cognitive symptoms predicted prior suicidal ideation. These findings were independent of comorbid major depressive disorder. It is suggested that assessment of suicide risk in the community includes the presentation of cognitive symptoms and symptoms related to alpha adrenergic activation.

Depersonalization disorder and anxiety: a special relationship?

A significant association between anxiety and depersonalization has been found in healthy controls and psychiatric patients irrespective of underlying conditions. Although patients with depersonalization disorder (DPD) often have a history of severe anxiety symptoms, clinical observations suggest that the relation between anxiety and depersonalization is complex and poorly understood. Using relevant rating scales, levels of anxiety and depersonalization were assessed in 291 consecutive DPD cases. 'High' and 'low' depersonalization groups, were compared according to anxiety severity. Correlation and multivariate regression analyses were also used to assessed the contribution of anxiety to the phenomenology and natural course of depersonalization. A low but significant association between depersonalization and anxiety (as measured by Beck's Anxiety Inventory) was only apparent in those patients with low intensity depersonalization, but not in those with severe depersonalization. Levels of anxiety did not seem to make specific contributions to the clinical features of depersonalization itself, although DPD patients with high anxiety seem characterised by additional non-specific perceptual symptoms. The presence of a 'statistical dissociation' between depersonalization and anxiety adds further evidence in favour of depersonalization disorder being an independent condition and suggests that its association with anxiety has been overemphasized.

Subtypes of panic attacks: a critical review of the empirical literature

BACKGROUND

Panic disorder is a heterogeneous disorder, comprising a variety of somatic, physiological, and cognitive symptoms during repeated panic attacks. As a result, considerable data have examined whether panic attacks may be classified into distinct diagnostic or functional subtypes. The aim of this study is to evaluate the existing literature regarding the validity of panic attack subtypes.

METHODS

This review focuses on data published since 2000, with the publication of DSM-IV-TR, augmented by replicated data published since 1980, with the publication of DSM-III and subsequently DSM-IV. Published reports evaluating empirical evidence for the validity of panic attack subtypes are reviewed.

RESULTS

Five sets of panic symptoms (respiratory, nocturnal, nonfearful, cognitive, and vestibular) have been shown to cluster together at varying degrees of consistency. However, none of these potential subtypes have been associated with sufficient and reliable external validation criteria indicative of functional differences. This apparent lack of findings may be related to methodological inconsistencies or limitations across the reviewed studies.

CONCLUSIONS

Although at present the data do not warrant the utility of subtyping, further research aimed at patent gaps in the literature, including clearer operationalization of symptom subtypes, greater use of biological challenge paradigms and physiological and other more objective measures of fear and anxiety, and exploration of subtyping based on biological factors such as genetics, may support the future designation of panic attack subtypes and their ultimate clinical utility.

The structure of emotional and cognitive anxiety symptoms

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

Regulatory processes and the development of cognitive representations

Although the construct of regulation is usually applied to ongoing behavior, it also has implications for ongoing cognition and the development of cognitive representations. We propose that subcortical motivational systems influence cortical representations in two general ways. First, they regulate response processes, promoting a general selection of information to which the child is exposed. Second, motivational systems regulate attention, promoting a more selective stabilization of representations for motivationally relevant sources of information. Together with the environment, these regulatory processes shape the child's developing representations. Individual differences in these processes result in cortical representational systems that enhance the motivational systems* ability to detect relevant inputs and to guide behavior in light of them. Examples are provided that focus on fearful children, discussing how their self-representation may contribute to anxious psychopathology.

The association between bodily anxiety symptom dimensions and the scales of the Revised NEO Personality Inventory and the Temperament and Character Inventory

The association between anxiety disorders and different measures of personality has been extensively studied to further the understanding of etiology, course, and treatment, and to possibly prevent the development of anxiety disorders. We have proposed a hierarchical model of bodily anxiety symptoms with 1 second-order severity factor and 5 first-order factors: cardio-respiratory, gastro-intestinal, autonomic, vertigo, and tension. The aim of this study was to investigate whether personality traits were differentially related to distinct symptom subdimensions or exclusively related to the general severity factor. Structural equation modeling of data on 120 patients with a primary diagnosis of social phobia and 207 patients with a primary diagnosis of panic disorder was used to examine the association between anxiety symptom dimensions and the scales of the Temperament and Character Inventory and of the Revised NEO Personality Inventory. When both sets of personality measures were simultaneously modeled as predictors, the Revised NEO Personality Inventory scales, neuroticism and extraversion, remained significantly associated with the severity factor, whereas the association between the Temperament and Character Inventory dimensions, harm avoidance and novelty seeking, and the severity factor became nonsignificant. Harm avoidance was negatively associated with the vertigo first-order factor, whereas neuroticism was negatively associated with the cardio-respiratory first-order factor, indicating that personality factors may be differentially related to specific anxiety subdimensions.

Depersonalization and individualism: the effect of culture on symptom profiles in panic disorder

It has been proposed that highly individualistic cultures confer vulnerability to depersonalization. To test this idea, we carried out a comprehensive systematic review of published empirical studies on panic disorder, which reported the frequency of depersonalization/derealization during panic attacks. It was predicted that the frequency of depersonalization would be higher in Western cultures and that a significant correlation would be found between the frequency of depersonalization and individualism scores of the participant countries. As predicted, the frequency of depersonalization during panic was significantly lower in nonwestern countries. There was also a significant correlation between frequency of depersonalization and Individualism (rho = 0.68, p < 0.0001), and between fears of losing control (rho = 0.57, p = 0.005) and individualism. These findings are interpreted in light of recent studies suggesting that individualistic cultures are characterized by hypersensitivity to threat and by an external locus of control. Two features may be relevant in the genesis of depersonalization.

Endorsement frequencies and factor structure of DSM-III-R and DSM-IV Generalized Anxiety Disorder symptoms in women: implications for future research, classification, clinical practice and comorbidity

We investigated dimensions of liability to Generalized Anxiety Disorder (GAD) and whether evidence exists for distinct pathological versus normal clusters in the population. Structured interviews were administered to a general population sample of 2,163 female twins in a cross-sectional design. Endorsement rates were estimated using full information maximum likelihood factor analyses of the DSM-III-R and DSM-IV GAD symptoms, which provides appropriate treatment of the stem-probe structure of the clinical interview. Endorsement rates were highest for symptoms retained in DSM-IV. For both DSM-III-R and DSM-IV, a two-factor model fit the data better than a single-factor model. There was no evidence for non-normality in the liability to GAD. For DSM-III-R, autonomic symptoms loaded on a factor with panic disorder, while fatiguability, difficulty concentrating and hypervigilance loaded on a factor with major depression. For DSM-IV, all items loaded on one factor, and muscle tension also loaded on a second. Major depression, panic, phobias and alcohol dependence diagnoses also loaded on the first factor.

CONCLUSIONS

Future research involving structured interviews should take into account the stem-and-probe format and focus on common factors rather than separate disorders; GAD is not a unidimensional construct and pathological anxiety may differ only quantitatively from normal anxiety.

An integrated cognitive model of panic disorder: The role of positive and negative cognitions

One reason for the neglect of the role of positive factors in cognitive-behavioural therapy (CBT) may relate to a failure to develop cognitive models that integrate positive and negative cognitions. Bandura [Psychol. Rev. 84 (1977) 191; Anxiety Res. 1 (1988) 77] proposed that self-efficacy beliefs mediate a range of emotional and behavioural outcomes. However, in panic disorder, cognitively based research to date has largely focused on catastrophic misinterpretation of bodily sensations. Although a number of studies support each of the predictions associated with the account of panic disorder that is based on the role of negative cognitions, a review of the literature indicated that a cognitively based explanation of the disorder may be considerably strengthened by inclusion of positive cognitions that emphasize control or coping. Evidence to support an Integrated Cognitive Model (ICM) of panic disorder was examined and the theoretical implications of this model were discussed in terms of both schema change and compensatory skills accounts of change processes in CBT.

A cross-cultural study of the structure of comorbidity among common psychopathological syndromes in the general health care setting

This study presents analyses of 7 common psychopathological syndromes in the World Health Organization (WHO) Collaborative Study of Psychological Problems in General Health Care (T. B. Ustun & N. Sartorius, 1995). Data on depression, somatization, hypochondriasis, neurasthenia, anxious worry, anxious arousal, and hazardous use of alcohol were analyzed for 14 countries (Ns for each country ranged from 196 to 800). Four models were evaluated: a 1-factor model; a 2-factor model in which all syndromes except hazardous use of alcohol represented internalizing problems; and two 3-factor models. The 2-factor model fit best. These results extend previous research on the 2-factor model to the current complaints of attendees of general health care clinics, to a new set of syndromes, and to a variety of both Western and non-Western countries.

The facets of anxiety sensitivity represented in the childhood anxiety sensitivity index: confirmatory analyses of factor models from past studies

Results of past factor analytic studies of the Childhood Anxiety Sensitivity Index and Anxiety Sensitivity Index were used to formulate hypotheses about factor models of anxiety sensitivity. Using a nonclinical sample of 767 children and adolescents and confirmatory factor analysis, hypothesized models with 2, 3, and 4 lower order factors (facets) were tested. Goodness-of-fit criteria indicated that a model with 4 facets fits these data well. Support was found for factorial invariance of the 4 facets across age and gender, using nonclinical and clinical samples. Results support a hierarchical factor model in that there was a strong general factor, explaining 71% of the variance. Findings are discussed in the context of anxiety sensitivity theory and research with children and adolescents.

Balance control and posture differences in the anxious BALB/cByJ mice compared to the non anxious C57BL/6J mice

A relation between anxiety disorders and balance control dysfunctions has been observed in many studies in humans. A mismatch in the integration of sensory inputs could trigger these disturbances. Very few experimental animal procedures have been designed to study the functional link between anxiety and balance control. A task was therefore developed, challenging the visual, vestibular and somesthesic sensory systems in mice. The test, called the 'rotating beam', gave an accurate assessment of balance control and the posture, using sensitive measures (number of falls and imbalances, position of tail and trunk). Striking differences were observed between the two inbred strains of mice known to have radically different anxiety-related behaviour. The highly anxious strain, BALB/cByJ, performed poorly compared to the non anxious strain, C57BL/6J. Balance control and postural abilities of anxious mice were improved by acute anxiolytic diazepam treatment. Lower behavioural performance level was registered in non anxious mice given anxiogenic beta-CCM treatment. The findings account for a strong relationship between anxiety and balance control in mice. Finally, the highly sensitive procedure proved to be well suited to the study of functional links between anxiety and sensorimotor processes.

Adaptation as a sensorial profile in trait anxiety: a study with virtual reality

Twenty-four volunteers were recruited on the basis of their trait anxiety scores (low trait anxiety [LTA] and high trait anxiety [HTA]) as assessed by the State-Trait Anxiety Inventory. Adaptation to conflicting visual-vestibular stimulation (VVS) was used to study integration of space-related multi-sensory information in trait anxiety. First, vestibular perception was assessed by rotating the blindfolded subjects about the vertical axis (horizontal plane rotations) on a remote-controlled mobile robot. The subjects were asked to indicate the perceived rotation by use of an angular pointer. Subjects were then immersed into the center of a visual virtual square room by means of a head-mounted display. They were asked to control the robot with a joystick in order to perform 90 degrees rotations in the virtual room. However, a gain of 0.5 was introduced between visual scene and robot rotation so that the subjects were submitted to a conflict situation in which the 90 degrees rotational visual input was concurrent with a 180 degrees vestibular input. After 45 min of training with the virtual reality display, subjects were tested again in total darkness in order to determine whether their vestibular system had been reset by the conflicting visual signals. We found significant differences in adaptation to VVS between HTA and LTA groups as well as between males and females. Subjects of the HTA group demonstrated larger adaptation than that of the LTA group. Males also showed a greater level of adaptation compared to females. Our results suggest greater visual dependence in HTA subjects. This might be important for understanding the mechanisms underlying pathological anxiety and particularly agoraphobia.

Psychosomatic symptoms and breathing pattern

OBJECTIVE

Study of the links between breathing pattern, negative affectivity, and psychosomatic complaints at rest and following hyperventilation.

METHODS

In 819 patients with anxiety and somatoform disorders and 159 healthy subjects, self-reported symptoms, breathing pattern, and end-tidal CO(2) concentration (FetCO(2)) were recorded during rest and following a hyperventilation provocation test (HVPT). The relationship between disorder category, symptoms, age, and score of STAI-trait (as a measure of negative affectivity) on the one hand, and breathing pattern on the other was investigated, separately in men and women.

RESULTS

Anxiety disorders, and to a lesser extent, somatoform disorders, were characterized by breathing instability (progressive decrease of FetCO(2) at rest during mouthpiece breathing, delayed recovery of FetCO(2) following HVPT), the mean values of respiratory frequency, and FetCO(2) being modulated by STAI-trait. After grouping the symptoms into independent factors, links were observed between symptoms and breathing pattern, independently from the presence of an anxiety or somatoform disorder.

CONCLUSION

Some symptom factors appeared to be related to a lower FetCO(2) during hyperventilation, others likely directly influenced the breathing pattern. Among those, mainly respiratory symptoms were accompanied by a reduction of FetCO(2) at rest, with slower recovery of FetCO(2) following HVPT. The latter was observed also in the presence of marked anxiety. In contrast, subjects complaining of dizziness, fainting, and paresthesias in daily life presented higher values of FetCO(2) following HVPT, probably due to a voluntary braking of ventilation during HVPT.

Depersonalization in panic disorder: a clinical study

Panic disorder (PD) has been hypothesized to be a heterogeneous entity, with distinct clinical subgroups. The presence of depersonalization during panic attacks may distinguish a specific subgroup of PD. We sought to analyze the differential features of a subgroup of PD patients with depersonalization. A total of 274 patients with PD were assessed and divided into 2 groups according to the presence or absence of depersonalization. The Structured Clinical Interview for DSM-III-R (SCID-UP-R) was used to assess PD and comorbid disorders. The clinical scales administered included the Hamilton Anxiety and Depression Rating Scale (HARS and HDRS), the Marks and Mathews Fears and Phobia Scale, Panic-Associated Symptom Scale (PASS), and a panic attack symptoms inventory. A total of 66 patients (24.1%) exhibited depersonalization during the attacks. Patients with depersonalization appeared to be younger and had an earlier age at onset. PD was more severe in the depersonalization group (greater number of attacks, worse level of functioning, and higher scores on most self-rating scales). Also, depersonalization patients showed more comorbidity with specific phobia. Our results support the view that PD with depersonalization may be considered a distinct and more severe subcategory of PD.

Semiology and subtyping of panic disorders

To date, the quantitative psychopathology of panic disorder (PD) has been less well studied than that of other psychiatric conditions such as schizophrenia or major depression. The aim of the present study was to assess the frequency and factorial grouping of symptoms in a naturalistic sample of PD patients. A total of 274 consecutive cases of PD who contacted an out-patient clinic in Barcelona, Spain were assessed by two experienced interviewers. The assessment instruments included the Structured Clinical Interview for DSM-III-R Upjohn version (SCID-UP-R) and an inventory of panic attack symptoms based on DSM-III-R. Of the patients who presented at the unit during the assessment period, 8.5% presented with PD. Palpitations, shortness of breath, fear of dying and dizziness were the most frequent and intense symptoms reported by the PD patients. Principal-component analysis revealed four factors which accounted for 57% of the variance, including 'cardiorespiratory' (26.1%) and 'vestibular' (15.1%) factors, and two additional factors with mixed symptoms. The frequency of presentation of symptoms was similar to that reported in other studies. However, some discrepancies were observed that may be attributed to transcultural differences as well as to terminological problems and the range of symptoms assessed. These factors may also explain some of the differences found in factor analysis groupings in previous studies. Our findings support the symptom subtyping of PD.

Towards a 'map' of panic: structure of the bodily symptoms

Despite the large amount of research on panic attacks according to DSM criteria, there are some inconsistencies between this and reports from clinical settings. Some naturalistic and non-standard studies are needed. The authors of the present study submitted a list of 24 bodily symptoms to 65 panic patients who had sought medical help. The results of principal-component analysis revealed five factors, four of which represent the forms described in clinical and epidemiological contexts: cephalo-vertiginous, cervico-respiratory, thoraco-cardiac and abdomino-digestive. Each of these factors is differentially related to some specific fearful anticipations, which may organize the symptoms in a body-related topographical way.

Panic disorder and vestibular disturbance: an overview of empirical findings and clinical implications

The purpose of this article is to provide a general overview of the growing literature on the relationship between panic disorder and vestibular disturbance. This relationship has been examined from two distinct perspectives, including: (a) the assessment of vestibular dysfunction in patients with panic disorder; and (b) the evaluation of panic symptomatology in patients with vestibular disturbance. Consequently, this review focuses primarily on the literature pertaining to vestibular symptoms in patients with panic disorder and panic symptomatology in patients with vestibular complaints. Subsequent to this review we discuss clinical implications suggested by the data, outline recommendations for treatment, and highlight some directions for future investigation.

Reliability and validity of the Overt Agitation Severity Scale in adult psychiatric inpatients

An instrument, that validly and reliably identifies and measures agitation is required to evaluate environmental modifications, interpersonal strategies, psychopharmacological interventions, directed toward managing these commonly occurring and highly-disabling emotions and behavior. The conceptualization of agitation on a continuum from anxiety to aggression provides a practical framework for guiding clinical practice toward the early identification and intervention of agitation. The results of this study established the reliability and validity of the Overt Agitation Severity Scale (OASS) in measuring agitation severity in young adult psychiatric inpatients based on objectifiable vocalizations and motoric upper and lower body behaviors. The OASS differs from other agitation scales in its ability to capture both the intensity and frequency of observable behavioral manifestations of agitation, as opposed to subjective interpretations and a diffuse range of symptoms and problem behaviors.

Anxiety sensitivity: theoretical perspectives and recent findings

Anxiety sensitivity (AS) is the fear of anxiety-related sensations, which arises from beliefs that these sensations have harmful somatic, psychological or social consequences. According to Reiss (1991), AS is one of three fundamental fears that amplify or cause many common fears. AS also is thought to play an important role in causing panic attacks. The purpose of the present article is to review recent findings concerning the construct of AS and its place in the nomological network outlined by Reiss. Although the weight of evidence supports a unifactorial model of AS, recent findings suggest AS is multifactorial at the level of first-order factors, and these factors load on a single higher-order factor. People with elevated AS, compared to those with low AS, are more likely to have histories of panic attacks. AS is factorially distinct from other fundamental fears, and is more strongly related to agoraphobia than other common fears. AS can be regarded as a subfactor of trait anxiety, and is more strongly related to agoraphobia than other common fears. AS can be regarded as a subfactor of trait anxiety, although the question arises as to whether AS is a cause of trait anxiety. Important questions for further investigation concern the etiology of AS and whether it can be reduced to still more basic fears.

The symptom structure of panic attacks

Panic attack symptomatology was investigated in 212 panic disorder patients (60 men, 152 women) using the Panic Attack Questionnaire, Feelings of helplessness and thoughts of escape had the highest mean severity ratings, but are not currently listed in the DSM-III-R. The DSM-III-R symptoms labeled choking or smothering sensations, paresthesias, nausea, and chest pain had low severity ratings. Evidence was obtained for a three-factor model of panic symptomatology consisting of dizziness-related symptoms, cardiorespiratory distress, and cognitive factors. These results provide only limited support for the current DSM-III-R symptom structure, and support the notion that panic disorder is a heterogeneous condition.

Risk factors for the incidence of social phobia as determined by the Diagnostic Interview Schedule in a population-based study

The Diagnostic Interview Schedule was used to identify 89 incident social phobia cases in wave 2 household subjects from 9437 at risk persons age 18 or older as part of the Epidemiologic Catchment Area study. Crude annual incidence of Diagnostic Interview Schedule/DSM-III social phobia was estimated at 9 per 1000 population per year. Onset of social phobia was associated with low education, never having been married and female gender. First onsets occurred throughout the life course of this adult sample. Nervousness, headache, panic spells, palpitations, other phobias, binge pattern of alcohol consumption, dysthymia and schizophrenic symptoms were also predictive of social phobia onset. There was no difference in predictive factors when "primary" social phobia (without premorbid panic) was analyzed separately.

Autorotation test abnormalities of the horizontal and vertical vestibulo-ocular reflexes in panic disorder

Patients with panic disorder often describe dizziness as a disturbing symptom, with more severe episodes reported than in other psychiatric populations. Nineteen patients diagnosed as having a panic disorder were tested for vestibulo-ocular (VOR) abnormalities with the Vestibular Autorotation Test (VAT), a computerized test of the high-frequency (2 to 6 Hz) VOR. The patients were unselected for the presence or absence of balance disorders. Results showed VOR abnormalities, relative to a normal population, in the horizontal and/or vertical VORs of all 19 patients. Vestibulo-ocular reflex asymmetries were commonly present. Because the VAT tested the VOR over a frequency range encountered during common daily activities, the observed abnormalities could result in a perceptually moving visual field (oscillopsia). We hypothesize that the resulting experience of a visual-vestibular disturbance--perhaps in a biologically or psychologically predisposed individual--is catastrophically misinterpreted, leading to more bodily symptoms and anxiety. These could then contribute to more misinterpretation in a positive feedback sense, ultimately leading to a panic attack.