Semiology and subtyping of panic disorders

Panic disorder respiratory subtype: psychopathology and challenge tests - an update

Panic disorder (PD) pathophysiology is very heterogeneous, and the discrimination of distinct subtypes could be very useful. A subtype based on respiratory symptoms is known to constitute a specific subgroup. However, evidence to support the respiratory subtype (RS) as a distinct subgroup of PD with a well-defined phenotype remains controversial. Studies have focused on characterization of the RS based on symptoms and response to CO2. In this line, we described clinical and biological aspects focused on symptomatology and CO2 challenge tests in PD RS. The main symptoms that characterize RS are dyspnea (shortness of breath) and a choking sensation. Moreover, patients with the RS tended to be more responsive to CO2 challenge tests, which triggered more panic attacks in this subgroup. Future studies should focus on discriminating respiratory-related clusters and exploring psychophysiological and neuroimaging outcomes in order to provide robust evidence to confirm RS as a distinct subtype of PD.

Panic attacks and panic disorder in the American Indian community

Panic disorder is a common mental health condition, but little is known about panic disorder in non-Caucasian populations. The purpose of this study is to describe the epidemiology, clinical features, and comorbidities of panic attacks and panic disorder in two large American Indian (AI) tribes (N=3084). A culturally-adapted version of the Composite International Diagnostic Interview assessed panic attacks, panic disorder, and various psychiatric comorbidities. After adjusting for age, gender, and tribe, linear and logistic regression analyses were conducted to compare AIs with panic disorder to those with panic attacks only on clinical characteristics and panic symptoms. Approximately 8.5% (N=234) of American Indians reported a lifetime history of panic attacks. Among individuals with panic attacks, comorbid posttraumatic stress disorder was higher in females (p=0.03) and comorbid alcohol-related disorders were higher in males (p≤0.001). The prevalence and clinical features of panic attacks and panic disorder in American Indians were similar to epidemiologic studies with majority populations. However, in contrast to earlier research, panic symptoms were similar in both males and females, and different patterns of comorbidity emerged. Future research should examine the availability and accessibility of evidence-based panic treatments for this traditionally underserved population.

Dimensional structure of bodily panic attack symptoms and their specific connections to panic cognitions, anxiety sensitivity and claustrophobic fears

BACKGROUND

Previous studies of the dimensional structure of panic attack symptoms have mostly identified a respiratory and a vestibular/mixed somatic dimension. Evidence for additional dimensions such as a cardiac dimension and the allocation of several of the panic attack symptom criteria is less consistent. Clarifying the dimensional structure of the panic attack symptoms should help to specify the relationship of potential risk factors like anxiety sensitivity and fear of suffocation to the experience of panic attacks and the development of panic disorder.

METHOD

In an outpatient multicentre study 350 panic patients with agoraphobia rated the intensity of each of the ten DSM-IV bodily symptoms during a typical panic attack. The factor structure of these data was investigated with nonlinear confirmatory factor analysis (CFA). The identified bodily symptom dimensions were related to panic cognitions, anxiety sensitivity and fear of suffocation by means of nonlinear structural equation modelling (SEM).

RESULTS

CFA indicated a respiratory, a vestibular/mixed somatic and a cardiac dimension of the bodily symptom criteria. These three factors were differentially associated with specific panic cognitions, different anxiety sensitivity facets and suffocation fear.

CONCLUSIONS

Taking into account the dimensional structure of panic attack symptoms may help to increase the specificity of the associations between the experience of panic attack symptoms and various panic related constructs.

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.

Smoking Behavior and Alcohol Consumption in Individuals With Panic Attacks

Individuals with anxiety often report greater smoking and drinking behaviors relative to those without a history of anxiety. In particular, smoking and alcohol use have been directly implicated among individuals experiencing panic attacks, diagnosed with panic disorder, or high on panic-relevant risk factors such as anxiety sensitivity. Less is known, however, about specific features of panic that may differentiate among those who do or do not use cigarettes or alcohol. The purpose of the current study was to replicate previous research findings of an association between panic symptomatology, cigarette smoking, and alcohol consumption, as well as extend findings by examining whether specific symptoms of panic attacks differentiated among those who do or do not use cigarettes or alcohol. Participants (n = 489) completed the Panic Attack Questionnaire-IV, a highly detailed assessment of panic attacks and symptoms, as well as self-report measures of smoking history and alcohol use. Consistent with previous research, participants who reported a history of panic attacks (n = 107) were significantly more likely to report current daily or lifetime daily cigarette smoking, and significantly greater hazardous or harmful alcohol use than participants with no panic history (n = 382). Although smoking and hazardous alcohol use were highly associated regardless of panic status, participants with panic attacks showed elevated hazardous alcohol use after controlling for daily or lifetime smoking. Surprisingly, although participants who reported having had at least one panic attack were more likely to smoke, panic attack symptoms, intensity, or frequency did not differentiate panickers who did or did not smoke. Furthermore, panic-related variables were not shown to differentially relate to problematic drinking among panickers. Implications for understanding the complex relationship between panic attacks and smoking and drinking behaviors are discussed.

Feeling lightheaded: the role of cerebral blood flow

OBJECTIVE

The main aims of this study were a) to investigate the relationship between lightheadedness and cerebral blood flow velocity (CBFv) during hyperventilation-induced hypocapnia, and b) to investigate whether and why the relationship between lightheadedness and CBFv may change after several episodes of this sensation.

METHODS

Three hypocapnic and three normocapnic overbreathing trials were administered in a semirandomized order to healthy participants (N = 33). Each type of breathing trial was consistently paired with one odor. Afterward, participants were presented each odor once in two spontaneous breathing and in two normocapnic overbreathing trials. CBFv in the right middle cerebral artery was measured by transcranial Doppler ultrasonography (TCD). Also breathing behavior and self-reported lightheadedness were measured continuously. Each trial was followed by a symptom checklist.

RESULTS

Self-reported lightheadedness was closely related to changes in CBFv in the hypocapnic overbreathing trials. During the subsequent normocapnic trials, however, participants experienced more lightheadedness and "feeling unreal" to the odor that had previously been paired with hyperventilation-induced hypocapnia. These complaints were not accompanied by changes in end-tidal CO(2) nor in CBFv.

CONCLUSIONS

The results show that lightheadedness is associated with changes in CBFv but that after a few episodes, the underlying mechanism for this symptom may shift to perceptual-cognitive processes. These findings may help to understand why lightheadedness occurs during emotional distress and panic. In addition, altered cerebral blood flow is unlikely to play a primary precipitating role in recurrent symptoms of lightheadedness.

Panic disorder respiratory subtype: psychopathology, laboratory challenge tests, and response to treatment

OBJECTIVE

Our objective is to summarize the new findings concerning the respiratory subtype (RS) of panic disorder (PD) since its first description.

METHODS

Two searches were made in the Institute for Scientific Information Web of Science: with the keywords "panic disorder" and "respiratory symptoms," and all articles that cited Briggs and colleagues' 1993 article "Subtyping of Panic Disorder by Symptom Profile" (Br J Psychiatry 1993;163:201-9). Altogether, 133 articles were reviewed.

RESULTS

We describe and discuss RS epidemiology, genetics, psychopathology, demographic features, clinical features, correlations with the respiratory system, traumatic suffocation history, provocative tests, and nocturnal panic. Compared to patients with the nonrespiratory subtype (non-RS), the RS patients had higher familial history of PD, lower comorbidity with depression, longer duration of illness, lower neuroticism scores, and higher scores in severity scales, such as the Panic and Agoraphobia Scale, Panic-Agoraphobia Spectrum scale and the Clinical Global Impression scale. Tests to induce panic attacks, such as those with CO(2), hyperventilation, and caffeine, produce panic attacks in a higher proportion of RS patients than non-RS patients. Differences in the subtypes' improvement with the pharmacologic treatment were found. There are also some controversial findings regarding the RS, including the age of onset of PD, and alcohol and tobacco use in RS patients.

CONCLUSIONS

Some characteristics, such as the increased sensitivity to CO(2) and the higher familial history of PD, clearly distinguish the RS from the non-RS. Nevertheless, there are also controversial findings. More studies are needed to determine the validity of the RS subtype.

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 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.

Is the association of hypertension and panic disorder explained by clustering of autonomic panic symptoms in hypertensive patients?

BACKGROUND

Autonomic nervous system dysfunction may be implicated in the association of hypertension with panic attacks and panic disorder. We hypothesised that panic symptoms of autonomic origin are more common in attacks experienced by hypertensive than normotensive patients, that autonomic panic symptoms cluster together as a distinct factor, and that this factor is more prevalent in hypertensive patients with panic than in normotensives.

METHODS

We analysed all 346 structured questionnaires completed by primary care and hospital clinic patients who had reported experiencing full (n=287) or limited symptom panic attacks (n=59) (268 with hypertension, and 78 never having had hypertension). Frequency of sweating, flushes, and racing heart, symptoms selected prospectively as being most likely of autonomic origin, were compared between hypertensive and normotensive patients. Principal component analysis was performed with varimax orthogonal rotation. Using logistic regression, odds ratios were calculated for association of factor scores with hypertension.

RESULTS

Sweating and flushes were significantly more common among hypertensive patients than normotensives (sweating; 65% v 46%, p=0.003, flushes; 55% v 40%, p=0.019). There was no significant difference between groups for frequency of racing heart nor any of the remaining panic symptoms analysed as secondary endpoints. Principal component analysis yielded four factors with eigenvalues >1.0. Factor 1 was dominated by autonomic symptoms, notably sweating and flushes, which had loadings of 0.68 and 0.61. On regression only this autonomic factor showed a significant association with hypertension, the odds ratio being 1.37 (95% C.I. 1.05 to 1.77, p=0.018).

CONCLUSIONS

These findings support the possibility that autonomic dysfunction contributes to the association of hypertension with panic.

Symptomspezifische Subgruppen der Panikstörung

Zusammenfassung. Theoretischer Hintergrund: In Modellen der Panikstörung wird eine erhöhte Sensitivität für körperliche Vorgänge angenommen. Die Spezifität dieser Sensitivität für verschiedene körperliche Funktionsbereiche ist unklar. Dies soll anhand der berichteten Symptome eines Panikanfalls geprüft werden. Methode: Die Angaben von 498 Panikpatienten zu 10 körperlichen Symptomen während eines typischen Panikanfalls (DSM-III-R) wurden Latent Class und Latent Class Faktorenanalysen unterzogen. Ergebnisse: Vier etwa gleichgroße Subgruppen von Panikpatienten mit unterschiedlichen Ausprägungen auf zwei binären Symptomfaktoren wurden identifiziert. Eine Gruppe hatte überwiegend respiratorische Symptome, eine weitere überwiegend vestibuläre Symptome. In den beiden übrigen Gruppen waren alle Symptome gleichermaßen stark bzw. schwach ausgeprägt. Schlussfolgerungen: Zwei der identifizierten Subgruppen scheinen spezifisch sensitiv für respiratorische bzw. vestibuläre Körpervorgänge zu sein. Für die verhaltenstherapeutische Panikbehandlung verweist dieser Befund darauf, spezifische Expositionsübungen zur Steigerung der Erfolgsquoten einzusetzen.

A new method for the assessment of spatial orientation and spatial anxiety in mice

The implication of integrated functional sensory relations of the body to space in anxiety disorders is a very important issue which encourages the development of animal models, in particular, for pharmacological perspectives and for the functional assessment of the deficits induced by genetic manipulation in the mouse or the rat. A new experimental device is presented here: It is comprised of a rotating tunnel and a rotating-beam controlled by computer which can be used for multiple visuo-idiothetic and kinesthetic sensory conflict situations during active locomotor behaviour by mice. The system is linked to a digital video system, Video-Track trade mark, designed to track and record the movements of the animals. Anxious BALB/cByJ mice were compared to non-anxious C57BL/6J mice and were seen to display highly disturbed locomotor behaviour in a sensory conflict situation. The model highlights the advantages of video-digital analysis for animal behavioural sciences.

Clinical features and co-morbidity of social phobics in Turkey

The aim of this study is to investigate the clinical features and frequency and importance of related co-morbid disorders of social phobia in a clinical sample. Eighty-seven patients meeting DSM-III-R diagnostic criteria for social phobia were studied. All patients were assessed by using a semi-structured socio-demographic form, the Structured Clinical Interview for DSM-III-R, Manual for the Structured Clinical Interview for DSM-III-R Personality Disorders, Liebowitz Social Anxiety Scale, Hamilton Rating Scale for Depression and Hamilton Rating Scale for Anxiety. Sixty-eight (78.2%) of the group were male, 19 (21.8%) were female. The ages varied between 16-58 years, with a mean of 26.2 years (SD = 8.5). Fifty-one point seven percent of the subjects were assessed as having a co-morbid axis I disorder, of which 12.6% consisted of panic disorder and 10.3% agoraphobia. An additional axis II disorder had been found in 67.8% of the subjects, and 54.0% of them had been diagnosed as having avoidant personality disorder. The frequency of co-morbid disorders in our social phobic sample is lower than most of the studies in the literature. The interface between social phobia and avoidant personality disorder needs to be studied and discussed further.

Diagnosis and treatment of psychologic symptoms and psychiatric disorders in patients with dizziness and imbalance

Patients with dizziness and psychopathology present diagnostic and therapeutic challenges to clinicians in several specialties. Clinical research is beginning to define the medical-psychiatric interactions that produce many of these patients' symptoms. Treatment research is still in its infancy. A model of illness progression is presented to guide physicians through the evaluation of this patient population. Treatment recommendations are based on current clinical experience.

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.

The development of agoraphobia in panic disorder: a predictable process?

BACKGROUND

Panic attacks are conceptualized to be the central feature of both panic disorder without (PDU) and with agoraphobia (PDA). As a sizeable percentage of panic patients do not develop avoidance behavior, other factors than 'panic attacks', in general, must influence the different courses of the disorder.

METHOD

We studied 84 outpatients suffering from PDU or PDA concerning different factors which were hypothesized to influence the development of agoraphobia.

RESULTS

'Earlier age of onset', 'fear of losing control' and 'chills or hot flushes' turned out to correlate statistically significantly with PDA, while 'chest pain or discomfort' occurred more often in PDU.

LIMITATIONS

The present study used retrospective data.

CONCLUSIONS

The results of this study suggest that the development of agoraphobia in panic disorder is influenced by specific variables and is not a purely coincidental process.

Differential clinical features of late-onset panic disorder

OBJECTIVES

The aim was to analyse the sociodemographic and clinical characteristics of panic disorder (PD) in patients with a PD onset after 60 years of age, at two outpatient psychiatric clinics in Barcelona (northeastern Spain).

MATERIAL AND METHODS

All patients presenting with PD at two outpatient clinics over a 4-year period were assessed by the same team. Patients with PD onset at 60 or after were grouped (late-onset), and compared with the group with an earlier onset. The instruments administered to the sample were: Global Assessment of Functioning scale, Panic-Associated Symptom Scale, Hamilton's Depression and Anxiety Scales and Marks-Matthews' Fear and Phobia scale.

RESULTS

Of 5301 patients attended over a 4-year period, 64 (1.2%) were PD patients aged 60 or above. Age at PD onset was over 60 in 27 cases (0.4% of the total population, and 6.1% of all PD patients). The mean age in the late-onset group was 67.0+/-4.9 years. Late-onset PD patients were less likely to report family history of PD. They scored lower on most scales assessing clinical severity (excepting GAF and agoraphobia scores), and they exhibited fewer and milder panic symptoms during the attacks. However, dysthymic disorder, but not major depressive disorder, was more common among late-onset PD patients (P<0.05).

COMMENTS

The most notable findings in our late-onset PD subgroup of patients were: lesser severity of the disorder, greater comorbidity with dysthymia, and less family history of PD. Prevalence rates of late-onset PD in our sample appeared to be rather high. Physical illness and less severe panic symptoms may contribute to underdiagnosing PD in this particular subpopulation.

Differential clinical features of early-onset panic disorder

BACKGROUND

Although panic disorder (PD) begins typically in adulthood, an earlier onset is not uncommon. Recent studies on early-onset PD indicate that this subgroup of patients may display distinct clinical characteristics.

OBJECTIVE

To compare a subgroup of early-onset PD patients with the rest of the sample.

METHOD

A consecutive series of 442 patients with PD were included. Family histories were investigated, and clinical assessment employed the following instruments: Hamilton's scales, Global Functioning Scale, Marks-Mathews' Fears and Phobia Scale, and Panic-Associated Symptom Scale. The age threshold for 'early-onset' was considered at 18 years.

RESULTS

A total of 45 patients (10.2%) exhibited early-onset PD, with a mean age at onset of 14.6. They were younger and had a longer duration of illness than later-onset patients. No differences were found in severity of panic symptoms, anxiety or depressive symptoms, and social functioning. They had more comorbidity with simple phobia, social phobia, and substance dependence. Rates of PD among first-degree relatives were higher in the early-onset group.

CONCLUSION

Early-onset PD patients displayed a greater familial loading, but clinical severity of their panic-agoraphobia symptoms was not higher. Comorbidity was greater with phobic and substance-related disorders.