Meta-analysis argues for a female-specific role of MAOA-uVNTR in panic disorder in four European populations

Panic disorder (PD) is a common mental disorder, ranking highest among the anxiety disorders in terms of disease burden. The pathogenesis of PD is multifactorial with significant heritability, however only a few convincing risk genes have been reported thus far. One of the most promising candidates is the gene encoding monoamine oxidase A (MAOA), due to its key role in monoaminergic neurotransmission, established validity of animal models, and the efficacy of MAO inhibitors in the treatment of PD. A promoter repeat polymorphism in MAOA (MAOA-uVNTR) impacts on gene expression; high-expression alleles have been reported to increase the risk for PD. To further scrutinize the role of this polymorphism, we performed a formal meta-analysis on MAOA-uVNTR and PD using original data from four published European (Estonian, German, Italian, and Polish) samples and genotypes from three hitherto unpublished German PD samples, resulting in the largest (n = 1,115 patients and n = 1,260 controls) genetic study on PD reported to date. In the unpublished samples, evidence for association of MAOA-uVNTR with PD was obtained in one of the three samples. Results of the meta-analysis revealed a significant and female-specific association when calculating an allelic model (OR = 1.23, P = 0.006). This sex-specific effect might be explained by a gene-dose effect causing higher MAOA expression in females. Taken together, our meta-analysis therefore argues that high-expression MAOA-uVNTR alleles significantly increase the risk towards PD in women. However, epigenetic mechanisms might obfuscate the genetic association, calling for ascertainment in larger samples as well as assessment of the MAOA promoter methylation status therein.

Dynamics of defensive reactivity in patients with panic disorder and agoraphobia: implications for the etiology of panic disorder

BACKGROUND

The learning perspective of panic disorder distinguishes between acute panic and anxious apprehension as distinct emotional states. Following animal models, these clinical entities reflect different stages of defensive reactivity depending upon the imminence of interoceptive or exteroceptive threat cues. The current study tested this model by investigating the dynamics of defensive reactivity in a large group of patients with panic disorder and agoraphobia (PD/AG).

METHODS

Three hundred forty-five PD/AG patients participated in a standardized behavioral avoidance test (being entrapped in a small, dark chamber for 10 minutes). Defense reactivity was assessed measuring avoidance and escape behavior, self-reports of anxiety and panic symptoms, autonomic arousal (heart rate and skin conductance), and potentiation of the startle reflex before and during exposure of the behavioral avoidance test.

RESULTS

Panic disorder and agoraphobia patients differed substantially in their defensive reactivity. While 31.6% of the patients showed strong anxious apprehension during this task (as indexed by increased reports of anxiety, elevated physiological arousal, and startle potentiation), 20.9% of the patients escaped from the test chamber. Active escape was initiated at the peak of the autonomic surge accompanied by an inhibition of the startle response as predicted by the animal model. These physiological responses resembled the pattern observed during the 34 reported panic attacks.

CONCLUSIONS

We found evidence that defensive reactivity in PD/AG patients is dynamically organized ranging from anxious apprehension to panic with increasing proximity of interoceptive threat. These data support the learning perspective of panic disorder.

Depression does not affect the treatment outcome of CBT for panic and agoraphobia: results from a multicenter randomized trial

BACKGROUND

Controversy surrounds the questions whether co-occurring depression has negative effects on cognitive-behavioral therapy (CBT) outcomes in patients with panic disorder (PD) and agoraphobia (AG) and whether treatment for PD and AG (PD/AG) also reduces depressive symptomatology.

METHODS

Post-hoc analyses of randomized clinical trial data of 369 outpatients with primary PD/AG (DSM-IV-TR criteria) treated with a 12-session manualized CBT (n = 301) and a waitlist control group (n = 68). Patients with comorbid depression (DSM-IV-TR major depression, dysthymia, or both: 43.2% CBT, 42.7% controls) were compared to patients without depression regarding anxiety and depression outcomes (Clinical Global Impression Scale [CGI], Hamilton Anxiety Rating Scale [HAM-A], number of panic attacks, Mobility Inventory [MI], Panic and Agoraphobia Scale, Beck Depression Inventory) at post-treatment and follow-up (categorical). Further, the role of severity of depressive symptoms on anxiety/depression outcome measures was examined (dimensional).

RESULTS

Comorbid depression did not have a significant overall effect on anxiety outcomes at post-treatment and follow-up, except for slightly diminished post-treatment effect sizes for clinician-rated CGI (p = 0.03) and HAM-A (p = 0.008) when adjusting for baseline anxiety severity. In the dimensional model, higher baseline depression scores were associated with lower effect sizes at post-treatment (except for MI), but not at follow-up (except for HAM-A). Depressive symptoms improved irrespective of the presence of depression.

CONCLUSIONS

Exposure-based CBT for primary PD/AG effectively reduces anxiety and depressive symptoms, irrespective of comorbid depression or depressive symptomatology.

Gender differences in associations of glutamate decarboxylase 1 gene (GAD1) variants with panic disorder

BACKGROUND

Panic disorder is common (5% prevalence) and females are twice as likely to be affected as males. The heritable component of panic disorder is estimated at 48%. Glutamic acid dehydrogenase GAD1, the key enzyme for the synthesis of the inhibitory and anxiolytic neurotransmitter GABA, is supposed to influence various mental disorders, including mood and anxiety disorders. In a recent association study in depression, which is highly comorbid with panic disorder, GAD1 risk allele associations were restricted to females.

METHODOLOGY/PRINCIPAL FINDINGS

Nineteen single nucleotide polymorphisms (SNPs) tagging the common variation in GAD1 were genotyped in two independent gender and age matched case-control samples (discovery sample n = 478; replication sample n = 584). Thirteen SNPs passed quality control and were examined for gender-specific enrichment of risk alleles associated with panic disorder by using logistic regression including a genotype×gender interaction term. The latter was found to be nominally significant for four SNPs (rs1978340, rs3762555, rs3749034, rs2241165) in the discovery sample; of note, the respective minor/risk alleles were associated with panic disorder only in females. These findings were not confirmed in the replication sample; however, the genotype×gender interaction of rs3749034 remained significant in the combined sample. Furthermore, this polymorphism showed a nominally significant association with the Agoraphobic Cognitions Questionnaire sum score.

CONCLUSIONS/SIGNIFICANCE

The present study represents the first systematic evaluation of gender-specific enrichment of risk alleles of the common SNP variation in the panic disorder candidate gene GAD1. Our tentative results provide a possible explanation for the higher susceptibility of females to panic disorder.

Effekte therapeutenbegleiteter versus patientengeleiteter Exposition bei Panikstörung mit Agoraphobie

Zusammenfassung. Theoretischer Hintergrund: Die Rolle der Therapeutenbegleitung während Expositionsübungen bei Panikstörung mit Agoraphobie (P/A) ist bislang ungeklärt. Eine kürzlich durchgeführte klinische Studie (MAC-Studie) lieferte Hinweise auf ein günstigeres Behandlungsergebnis bei Therapeutenbegleitung. Fragestellung: Wie lassen sich Effekte therapeutenbegleiteter Exposition (T+) im Vergleich zu Exposition ohne Therapeutenbegleitung (T–) erklären? Methode: Daten von 301 Patienten, die eine expositionsbasierte KVT mit bzw. ohne Therapeutenbegleitung erhalten hatten, wurden analysiert. Untersucht wurden der Einfluss der initialen Störungsschwere, des Sicherheitsverhaltens sowie differenzielle Effekte der Bedingungen auf die Angst vor der Angst. Zusätzlich wurde überprüft, inwieweit die Übungshäufigkeit in den Behandlungsbedingungen variiert und einen Mediator des Behandlungserfolgs darstellt. Ergebnisse: Störungsschwere und Sicherheitsverhalten zeigten keine differenziellen Effekte zwischen den Bedingungen; die T+ Bedingung führte jedoch zu stärkeren Reduktionen der Angst vor der Angst im Angstsensitivitätsindex. Patienten der T+ Bedingung führten häufiger selbständig Expositionsübungen durch, während Patienten in T– im Durchschnitt länger übten. Die Übungshäufigkeit stellte dabei einen Mediator des Behandlungserfolgs dar. Schlussfolgerungen: Günstigere Effekte einer therapeutenbegleiteten Exposition gehen auf stärkere Reduktionen der Angst vor der Angst sowie auf eine höhere Übungshäufigkeit im Selbstmanagement zurück.

The relation between disgust-sensitivity, blood-injection-injury fears and vasovagal symptoms in blood donors: disgust sensitivity cannot explain fainting or blood donation-related symptoms

BACKGROUND AND OBJECTIVES

Page's (1994) prominent theory for the explanation of fainting in blood-injection-injury situations holds that disgust sensitivity contributes to syncopal reactions. We investigated if blood donation-related vasovagal symptoms (1) or fainting related to blood donations (2) are associated with disgust sensitivity.

METHODS

In an online sample of 361 blood donors, we assessed blood-injection-injury fears, disgust sensitivity, history of blood donation related fainting and retrospective self-ratings of vasovagal symptoms. For the assessment of blood-injection-injury fears we used the BII-Q which has excellent psychometric properties and does not confound disgust and anxiety sensitivity. Vasovagal symptoms were measured by the Blood Donation Reactions Inventory (BDRI) which captures mild and strong vasovagal symptoms and has been used in previous studies with blood donors.

RESULTS

Disgust sensitivity did not significantly contribute to the explanation of self-reported vasovagal symptoms in a regression model with gender, blood-injection-injury fear and disgust sensitivity as predictors. We did not find any significant group differences in disgust sensitivity for blood donors with or without a fainting history (statistical power = 0.95) and a Bayesian model selection procedure showed that it is more likely that both groups are equally disgust sensitive than it is that the fainters are more disgust sensitive.

LIMITATIONS

Further research is required to confirm the findings in prospective studies.

CONCLUSION

Our results indicate that disgust sensitivity is not relevant for the development of vasovagal syncopes.

Diagnostik der Blut-Verletzungs-Spritzen-Angst

Zusammenfassung. Theoretischer Hintergrund: Zur Erfassung von Blut-Verletzungs-Spritzen-Ängsten sollte für den deutschen Sprachraum ein valider Fragebogen mit klarer Faktorenstruktur entwickelt werden. Fragestellung: Entwicklung eines neuen Messinstrumentes, welches auf die Erhebung von Blut-Verletzungs-Spritzen-Ängstlichkeit fokussiert. Methode: Entwicklung und Validierung eines Fragebogens an 340 Studenten, 20 Phobikern, 20 Kontrollpersonen und 18 Blutspendern. Ergebnisse: Es ergab sich ein Fragebogen mit 20 Items. Die Retest-Korrelation war hoch (rtt(42) = .78). Die Validitätsanalyse ergab hohe Korrelationen mit konstruktnahen Fragebögen, niedrige Korrelationen mit konstruktfernen Fragebögen und eine gute Differenzierung zwischen Phobikern und Kontrollpersonen. Ab einem Cut-Off von 44 (Range 20 bis 140) sollte das Vorliegen einer Blut-Verletzungs-Spritzen-Phobie geprüft werden. Schlussfolgerungen: Es konnte ein reliabler und valider deutscher Fragebogen mit vier klar definierten Faktoren entwickelt werden.

(Don't) panic in the scanner! How panic patients with agoraphobia experience a functional magnetic resonance imaging session

Although functional magnetic resonance imaging (fMRI) has gained increasing importance in investigating neural substrates of anxiety disorders, less is known about the stress eliciting properties of the scanner environment itself. The aim of the study was to investigate feasibility, self-reported distress and anxiety management strategies during an fMRI experiment in a comprehensive sample of patients with panic disorder and agoraphobia (PD/AG). Within the national research network PANIC-NET, n=89 patients and n=90 controls participated in a multicenter fMRI study. Subjects completed a retrospective questionnaire on self-reported distress, including a habituation profile and exploratory questions about helpful strategies. Drop-out rates and fMRI quality parameters were employed as markers of study feasibility. Different anxiety measures were used to identify patients particularly vulnerable to increased scanner anxiety and impaired data quality. Three (3.5%) patients terminated the session prematurely. While drop-out rates were comparable for patients and controls, data quality was moderately impaired in patients. Distress was significantly elevated in patients compared to controls; claustrophobic anxiety was furthermore associated with pronounced distress and lower fMRI data quality in patients. Patients reported helpful strategies, including motivational factors and cognitive coping strategies. The feasibility of large-scale fMRI studies on PD/AG patients could be proved. Study designs should nevertheless acknowledge that the MRI setting may enhance stress reactions. Future studies are needed to investigate the relationship between self-reported distress and fMRI data in patient groups that are subject to neuroimaging research.

Eye movement assessment in individuals with social phobia: differential usefulness for varying presentation times?

Visual dot probe tasks are used to examine attentional biases towards threat faces in social phobia. Based on eye movement assessments, short presentation times of stimuli have been proposed to investigate initial attentional processes. However, it remains unclear if eye movements contribute to anxiety related biases as measured in dot probe tasks when presentation times below 200 ms are used. In this study the electrooculogram (EOG) was recorded in a sample of 17 participants with social phobia and 13 controls performing a visual dot probe task in two presentation time conditions. In the 175 ms condition, half of the participants moved their eyes in only 10% of the trials. Significantly more participants moved their eyes in the 600 ms condition and individuals with social phobia directed their gaze more often to the threat faces than to the neutral faces. Eye movement measures were not related to reaction time measures but the number of initial eye movements towards threatening faces correlated with measures of social anxiety. For dot probe paradigms, the additional use of eye movement measures seems to be particularly appropriate for longer presentation times. The dissociation between attentional bias scores as measured with reaction time versus eye movement measures and their relation to different presentation times underlines the need for both measures when conducting visual probe studies.

Psychometrische Gütekriterien des Metakognitionsfragebogens (Kurzversion, MKF-30)

Zusammenfassung. Theoretischer Hintergrund: Metakognitionen wird für das Verständnis verschiedener psychischer Störungen eine wichtige Rolle beigemessen. So kann z.B. übermäßiges Sorgen durch Metakognitionen ausgelöst und aufrechterhalten werden. Fragestellung: Ziel dieser Arbeit war die systematische psychometrische Untersuchung der deutschen Kurzform des Metacognition Questionnaire (MKF-30). Methode: Mittels einer Teilstichprobe (N = 1168) wurde explorativ die Faktorenstruktur des MKF-30 ermittelt. Die ermittelte 5-Faktorenstruktur wurde anschließend konfirmiert (Teilstichprobe 2: N = 1155). Zur Konstruktvalidierung wurden Angst- sowie ein Depressionsfragebogen eingesetzt. Ergebnisse: Es ließen sich die fünf Faktoren des englischen Originals replizieren und konfirmieren. Die Analysen der Itemkennwerte sowie der konvergenten Validität lieferten insgesamt gute Ergebnisse. Schlussfolgerungen: Der MKF-30 kann vorläufig als ein reliables, valides und ökonomisches Instrument zur Erfassung von Metakognitionen angesehen werden.

Airway response to emotion- and disease-specific films in asthma, blood phobia, and health

Earlier research found autonomic and airway reactivity in asthma patients when they were exposed to blood-injection-injury (BII) stimuli. We studied oscillatory resistance (R(os)) in asthma and BII phobia during emotional and disease-relevant films and examined whether muscle tension counteracts emotion-induced airway constriction. Fifteen asthma patients, 12 BII phobia patients, and 14 healthy controls viewed one set of negative, positive, neutral, BII-related, and asthma-related films with leg muscle tension and a second set without. R(os), ventilation, cardiovascular activity, and skin conductance were measured continuously. R(os) was higher during emotional compared to neutral films, particularly during BII material, and responses increased from healthy over asthmatic to BII phobia participants. Leg muscle tension did not abolish R(os) increases. Thus, the airways are particularly responsive to BII-relevant stimuli, which could become risk factors for asthma patients.

Effects of alcohol on the processing of social threat-related stimuli in socially phobic women

BACKGROUND

Social phobics are at a higher risk of developing alcohol problems. The mechanism promoting this association is not clear. According to Sayette (1993b), alcohol attenuates anxiety responses by disrupting initial appraisal of threatening stimuli. We used the emotional Stroop test and an implicit memory test to investigate whether alcohol hinders appraisal of social threat words in patients diagnosed with social phobia.

PROCEDURE

Thirty-two women with social phobia (DSM-IV) and 32 female controls performed an emotional Stroop test either after drinking alcohol resulting in a blood alcohol levels (BAL) of 0.6%. or after drinking a non-alcoholic beverage. The emotional Stroop test contained social anxiety-related and neutral stimuli. Implicit memory for the words presented was tested with a word-stem completion test.

RESULTS

Without alcohol, both controls and socially-phobic participants took longer to name the colour of socially-threatening stimuli than of neutral stimuli. Alcohol levelled response latencies to the two stimulus categories only in controls. Socially-phobic participants responded more slowly to social anxiety-related stimuli than to neutral stimuli, irrespective of their BAL. In contrast to controls, social phobics showed an implicit memory bias for social threat words. This bias was attenuated by alcohol.

DISCUSSION

Alcohol disrupts appraisal of social anxiety-related stimuli in controls but not in social phobics; in these it hinders the consolidation of memory. This also suggests that social phobics experience similar anxiety with and without alcohol, but remember this experienced anxiety less precisely. This effect might act as a reinforcer for the use of alcohol for the purpose of self-medication in future situations.

Heartbeat perception in social anxiety before and during speech anticipation

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

Dimensional structure of the Social Interaction Anxiety Scale according to the analysis of data obtained with a German version

The Social Interaction and Anxiety Scale (SIAS) is widely used to assess social interaction anxiety. Yet its dimensional structure is still not well-defined. Especially, the conceptual pertinence of three negatively keyed items has been challenged. In this study, dimensionality of the answers of a student sample to a German SIAS version was first analyzed exploratorily. Subsequently, we tested confirmatorily several measurement models specifying different SIAS dimensions, and investigated how these relate to extraversion. The most reasonable model was cross-validated relying on data from healthy controls and social phobia sufferers. All analyses involved methods suited for an adequate handling of ordinal data. The findings confirm that three negatively keyed items are dubious indicators of social interaction anxiety. Thus, only the remaining 17 items should be used for this purpose in future studies. Analyses of their psychometric properties show, in addition, that they apparently tap three different facets of social interaction anxiety.

Coincidence of paroxysmal supraventricular tachycardia and panic disorder: two case reports

Panic disorder (PD) is characterised by sudden attacks of intense fear with somatic symptoms including palpitations and tachycardia. Reciprocally, palpitations caused by paroxysmal supraventricular tachycardia (PSVT) are commonly associated with anxiety and may therefore be misdiagnosed as PD. As demonstrated by two case reports, PSVT and PD can occur comorbidly in a chronological sequence, with PSVT possibly precipitating and maintaining PD via interoceptive processes or, alternatively, with PD increasing the risk for PSVT by elevating stress levels. As both PSVT and PD require different treatments, potentially helpful differential clinical diagnostic criteria are proposed.

Mechanism of action in CBT (MAC): methods of a multi-center randomized controlled trial in 369 patients with panic disorder and agoraphobia

Cognitive behavioral therapy (CBT) is efficacious for panic disorder with agoraphobia (PD/A). Nevertheless, the active ingredients of treatment and the mechanisms through which CBT achieves its effects remain largely unknown. The mechanisms of action in CBT (MAC) study was established to investigate these questions in 369 patients diagnosed with PD/A. The MAC study utilized a multi-center, randomized controlled design, with two active treatment conditions in which the administration of exposure was varied, and a wait-list control group. The special feature of MAC is the way in which imbedded experimental, psychophysiological, and neurobiological paradigms were included to elucidate therapeutic and psychopathological processes. This paper describes the aims and goals of the MAC study and the methods utilized to achieve them. All aspects of the research design (e.g., assessments, treatment, experimental procedures) were implemented so as to facilitate the detection of active therapeutic components, and the mediators and moderators of therapeutic change. To this end, clinical, behavioral, physiological, experimental, and genetic data were collected and will be integrated.

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

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