Effects of Cognitive Behavioral Therapy on Neural Processing of Agoraphobia-Specific Stimuli in Panic Disorder and Agoraphobia.

BACKGROUND: Patients suffering from panic disorder and agoraphobia are significantly impaired in daily life due to anxiety about getting into a situation due to apprehension about experiencing a panic attack, especially if escape may be difficult. Dysfunctional beliefs and behavior can be changed with cognitive behavioral therapy; however, the neurobiological effects of such an intervention on the anticipation and observation of agoraphobia-specific stimuli are unknown. METHODS: We compared changes in neural activation by measuring the blood oxygen level-dependent signal of 51 patients and 51 healthy controls between scans before and those after treatment (group by time interaction) during anticipation and observation of agoraphobia-specific compared to neutral pictures using 3-T fMRI. RESULTS: A significant group by time interaction was observed in the ventral striatum during anticipation and in the right amygdala during observation of agoraphobia-specific pictures; the patients displayed a decrease in ventral striatal activation during anticipation from pre- to posttreatment scans, which correlated with clinical improvement measured with the Mobility Inventory. During observation, the patients displayed decreased activation in the amygdala. These activational changes were not observed in the matched healthy controls. CONCLUSIONS: For the first time, neural effects of cognitive behavioral therapy were shown in patients suffering from panic disorder and agoraphobia using disorder-specific stimuli. The decrease in activation in the ventral striatum indicates that cognitive behavioral therapy modifies anticipatory anxiety and may ameliorate abnormally heightened salience attribution to expected threatening stimuli. The decreased amygdala activation in response to agoraphobia-specific stimuli indicates that cognitive behavioral therapy can alter the basal processing of agoraphobia-specific stimuli in a core region of the fear network.

Therapygenetics: anterior cingulate cortex-amygdala coupling is associated with 5-HTTLPR and treatment response in panic disorder with agoraphobia.

Variation in the 5'-flanking promoter region of the serotonin transporter gene SLC6A4, the 5-HTT-linked polymorphic region (5-HTTLPR) has been inconclusively associated with response to cognitive-behavioural therapy (CBT). As genomic functions are stronger related to neural than to behavioural markers, we investigated the association of treatment response, 5-HTTLPR and functional brain connectivity in patients with panic disorder with agoraphobia (PD/AG). Within the national research network PANIC-NET 231 PD/AG patients who provided genetic information underwent a manualized exposure-based CBT. A subset of 41 patients participated in a functional magnetic resonance imaging (fMRI) add-on study prior to treatment applying a differential fear conditioning task. Neither the treatment nor the reduced fMRI sample showed a direct effect of 5-HTTLPR on treatment response as defined by a reduction in the Hamilton Anxiety Scale score ≥50 % from baseline to post assessment. On a neural level, inhibitory anterior cingulate cortex (ACC)-amygdala coupling during fear conditioning that had previously been shown to characterize treatment response in this sample was driven by responders with the L/L genotype. Building upon conclusive evidence from basic and preclinical findings on the association of the 5-HTTLPR polymorphism with emotion regulation and related brain connectivity patterns, present findings translate these to a clinical sample of PD/AG patients and point towards a potential intermediate connectivity phenotype modulating response to exposure-based CBT.

Neural correlates of procedural variants in cognitive-behavioral therapy: a randomized, controlled multicenter FMRI study.

BACKGROUND: Cognitive behavioral therapy (CBT) is an effective treatment for panic disorder with agoraphobia (PD/AG). It is unknown, how variants of CBT differentially modulate brain networks involved in PD/AG. This study was aimed to evaluate the effects of therapist-guided (T+) versus self-guided (T-) exposure on the neural correlates of fear conditioning in PD/AG. METHOD: In a randomized, controlled multicenter clinical trial in medication-free patients with PD/AG who were treated with 12 sessions of manualized CBT, functional magnetic resonance imaging (fMRI) was used during fear conditioning before (t1) and after CBT (t2). Quality-controlled fMRI data from 42 patients and 42 healthy subjects (HS) were obtained. Patients were randomized to two variants of CBT (T+, n = 22, and T-, n = 20). RESULTS: The interaction of diagnosis (PD/AG, HS), treatment group (T+, T-), time point (t1, t2) and stimulus type (conditioned stimulus: yes, no) revealed activation in the left hippocampus and the occipitotemporal cortex. The T+ group demonstrated increased activation of the hippocampus at t2 (t2 > t1), which was positively correlated with treatment outcome, and a decreased connectivity between the left inferior frontal gyrus and the left hippocampus across time (t1 > t2). CONCLUSION: After T+ exposure, contingency-encoding processes related to the posterior hippocampus are augmented and more decoupled from processes of the left inferior frontal gyrus, previously shown to be dysfunctionally activated in PD/AG. Linking single procedural variants to neural substrates offers the potential to inform about the optimization of targeted psychotherapeutic interventions.

Delineating self-referential processing from episodic memory retrieval: common and dissociable networks.

Self-referential processing involves a complex set of cognitive functions, posing challenges to delineating its independent neural correlates. While self-referential processing has been considered functionally intertwined with episodic memory, the present study explores their overlap and dissociability. Standard tasks for self-referential processing and episodic memory were combined into a single fMRI experiment. Contrasting the effects of self-relatedness and retrieval success allowed for the two processes to be delineated. Stimuli judged as self-referential specifically activated the posterior cingulate/anterior precuneus, the medial prefrontal cortex, and an inferior division of the inferior parietal lobule. In contrast, episodic memory retrieval specifically involved the posterior precuneus, the right anterior prefrontal cortex, and a superior division of the inferior parietal lobule (extending into superior parietal lobule). Overlapping activations were found in intermediate zones in the precuneus and the inferior parietal lobule, but not in the prefrontal cortex. While our data show common networks for both processes in the medial and lateral parietal cortex, three functional differentiations were also observed: (1) an anterior-posterior differentiation within the medial parietal cortex; (2) a medial-anterolateral differentiation within the prefrontal cortex; and, (3) an inferior-superior differentiation within the lateral parietal cortex for self-referential processing versus episodic memory retrieval.

The modulating impact of cigarette smoking on brain structure in panic disorder: a voxel-based morphometry study.

Cigarette smoking increases the likelihood of developing anxiety disorders, among them panic disorder (PD). While brain structures altered by smoking partly overlap with morphological changes identified in PD, the modulating impact of smoking as a potential confounder on structural alterations in PD has not yet been addressed. In total, 143 PD patients (71 smokers) and 178 healthy controls (62 smokers) participated in a multicenter magnetic resonance imaging (MRI) study. T1-weighted images were used to examine brain structural alterations using voxel-based morphometry in a priori defined regions of the defensive system network. PD was associated with gray matter volume reductions in the amygdala and hippocampus. This difference was driven by non-smokers and absent in smoking subjects. Bilateral amygdala volumes were reduced with increasing health burden (neither PD nor smoking > either PD or smoking > both PD and smoking). As smoking can narrow or diminish commonly observed structural abnormalities in PD, the effect of smoking should be considered in MRI studies focusing on patients with pathological forms of fear and anxiety. Future studies are needed to determine if smoking may increase the risk for subsequent psychopathology via brain functional or structural alterations.

Effect of CBT on Biased Semantic Network in Panic Disorder: A Multicenter fMRI Study Using Semantic Priming.

OBJECTIVE: Cognitive-behavioral therapy (CBT) has been hypothesized to act by reducing the pathologically enhanced semantic, anxiety-related associations of patients with panic disorder. This study investigated the effects of CBT on the behavioral and neural correlates of the panic-related semantic network in patients with panic disorder. METHODS: An automatic semantic priming paradigm specifically tailored for panic disorder, in which panic symptoms (e.g., "dizziness") were primed by panic triggers (e.g., "elevator") compared with neutral words (e.g., "bottle"), was performed during functional MRI scanning with 118 patients with panic disorder (compared with 150 healthy control subjects) before and 42 patients (compared with 52 healthy control subjects) after an exposure-based CBT. Neural correlates were investigated by comparing 103 pairs of matched patients and control subjects at the baseline (for patients) or T1 (for control subjects) assessment and 39 pairs at the posttreatment or T2 assessment. RESULTS: At baseline or T1, patients rated panic-trigger/panic-symptom word pairs with higher relatedness and higher negative valence compared with healthy control subjects. Patients made faster lexical decisions to the panic-symptom words when they were preceded by panic-trigger words. This panic-priming effect in patients (compared with control subjects) was reflected in suppressed neural activation in the left and right temporal cortices and insulae and enhanced activation in the posterior and anterior cingulate cortices. After CBT, significant clinical improvements in the patient group were observed along with a reduction in relatedness and negative valence rating and attenuation of neural activation in the anterior cingulate cortex for processing of panic-trigger/panic-symptom word pairs. CONCLUSIONS: The findings support a biased semantic network in panic disorder, which is normalized after CBT. Attenuation of anterior cingulate cortex activation for processing of panic-related associations provides a potential mechanism for future therapeutic interventions.

The impact of depressive comorbidity on neural plasticity following cognitive-behavioral therapy in panic disorder with agoraphobia.

BACKGROUND: Depressive disorders are a frequent comorbidity of panic disorder with agoraphobia (PD/AG). Cognitive-behavioral therapy (CBT) for PD/AG effectively reduces anxiety and depressive symptoms, irrespective of comorbidities. However, as depressive comorbidities can confound fear circuitry activation (i.e. amygdalae, insulae, anterior cingulate cortex) in PD/AG, we investigated whether comorbid depressive disorders alter neural plasticity following CBT. METHODS: Within a randomized, controlled clinical trial on exposure-based CBT, forty-two PD/AG patients including fifteen (35.7%) with a comorbid depressive disorder (PD/AG + DEP) participated in a longitudinal functional magnetic resonance imaging (fMRI) study. A differential fear conditioning task was used as probe of interest. A generalized psycho-physiological interaction analysis (gPPI) served to study functional connectivity patterns. RESULTS: After CBT, only PD/AG patients without comorbid depressive disorders (PD/AG-DEP) showed reduced activation in the left inferior frontal gyrus (IFG) extending to the insula. While PD/AG-DEP patients showed enhanced functional connectivity (FC) between the left IFG and subcortical structures (anterior cingulate cortex, thalamus and midbrain), PD/AG + DEP patients exhibited increased FC between the left IFG and cortical structures (prefrontal, parietal regions). In both groups, FC decreased following CBT. LIMITATIONS: Primary depressed and medicated patients were excluded. Major depression and dysthymia were collapsed. CONCLUSIONS: Reduced activation in the left IFG, as previously shown in PD/AG, appears to be a specific substrate of CBT effects in PD/AG-DEP patients only. Differential patterns of FC pertaining to fear circuitry networks in patients without depression vs. cognitive networks in patients with comorbid depression may point towards different pathways recruited by CBT as a function of comorbidity.

Association of NPSR1 gene variation and neural activity in patients with panic disorder and agoraphobia and healthy controls.

INTRODUCTION: The neurobiological mechanisms behind panic disorder with agoraphobia (PD/AG) are not completely explored. The functional A/T single nucleotide polymorphism (SNP) rs324981 in the neuropeptide S receptor gene (NPSR1) has repeatedly been associated with panic disorder and might partly drive function respectively dysfunction of the neural "fear network". We aimed to investigate whether the NPSR1 T risk allele was associated with malfunctioning in a fronto-limbic network during the anticipation and perception of agoraphobia-specific stimuli. METHOD: 121 patients with PD/AG and 77 healthy controls (HC) underwent functional magnetic resonance imaging (fMRI) using the disorder specific "Westphal-Paradigm". It consists of neutral and agoraphobia-specific pictures, half of the pictures were cued to induce anticipatory anxiety. RESULTS: Risk allele carriers showed significantly higher amygdala activation during the perception of agoraphobia-specific stimuli than A/A homozygotes. A linear group x genotype interaction during the perception of agoraphobia-specific stimuli showed a strong trend towards significance. Patients with the one or two T alleles displayed the highest and HC with the A/A genotype the lowest activation in the inferior orbitofrontal cortex (iOFC). DISCUSSION: The study demonstrates an association of the NPSR1rs324981 genotype and the perception of agoraphobia-specific stimuli. These results support the assumption of a fronto-limbic dysfunction as an intermediate phenotype of PD/AG.

Reward and loss anticipation in panic disorder: An fMRI study.

Anticipatory anxiety and harm avoidance are essential features of panic disorder (PD) and may involve deficits in the reward system of the brain, in particular in the ventral striatum. While neuroimaging studies on PD have focused on fearful and negative affective stimulus processing, no investigations have directly addressed deficits in reward and loss anticipation. To determine whether the ventral striatum shows abnormal neural activity in PD patients during anticipation of loss or gain, an event-related functional magnetic resonance imaging experiment using a monetary incentive delay task was employed in 10 patients with PD and 10 healthy controls. A repeated-measures ANOVA to identify effects of group (PD vs. Control) and condition (anticipation of loss vs. gain vs. neutral outcome) revealed that patients with PD showed significantly reduced bilateral ventral striatal activation during reward anticipation but increased activity during loss anticipation. Within the patient group, the degree of activation in the ventral striatum during loss-anticipation was positively correlated with harm avoidance and negatively correlated with novelty seeking. These findings suggest that behavioural impairments in panic disorder may be related to abnormal neural processing of motivational cues.

Support Vector Machine Analysis of Functional Magnetic Resonance Imaging of Interoception Does Not Reliably Predict Individual Outcomes of Cognitive Behavioral Therapy in Panic Disorder with Agoraphobia.

BACKGROUND: The approach to apply multivariate pattern analyses based on neuro imaging data for outcome prediction holds out the prospect to improve therapeutic decisions in mental disorders. Patients suffering from panic disorder with agoraphobia (PD/AG) often exhibit an increased perception of bodily sensations. The purpose of this investigation was to assess whether multivariate classification applied to a functional magnetic resonance imaging (fMRI) interoception paradigm can predict individual responses to cognitive behavioral therapy (CBT) in PD/AG. METHODS: This analysis is based on pretreatment fMRI data during an interoceptive challenge from a multicenter trial of the German PANIC-NET. Patients with DSM-IV PD/AG were dichotomized as responders (n = 30) or non-responders (n = 29) based on the primary outcome (Hamilton Anxiety Scale Reduction ≥50%) after 6 weeks of CBT (2 h/week). fMRI parametric maps were used as features for response classification with linear support vector machines (SVM) with or without automated feature selection. Predictive accuracies were assessed using cross validation and permutation testing. The influence of methodological parameters and the predictive ability for specific interoception-related symptom reduction were further evaluated. RESULTS: SVM did not reach sufficient overall predictive accuracies (38.0-54.2%) for anxiety reduction in the primary outcome. In the exploratory analyses, better accuracies (66.7%) were achieved for predicting interoception-specific symptom relief as an alternative outcome domain. Subtle information regarding this alternative response criterion but not the primary outcome was revealed by post hoc univariate comparisons. CONCLUSION: In contrast to reports on other neurofunctional probes, SVM based on an interoception paradigm was not able to reliably predict individual response to CBT. Results speak against the clinical applicability of this technique.

Affective responses across psychiatric disorders-A dimensional approach.

Studying psychiatric disorders across nosological boundaries aims at a better understanding of mental disorders by identifying comprehensive signatures of core symptoms. Here, we studied neurobiological correlates of emotion processing in several major psychiatric disorders. We assessed differences between diagnostic groups, and investigated whether there is a psychopathological correlate of emotion processing that transcends disorder categories. 135 patient with psychiatric disorders (alcohol dependence, n=29; schizophrenia, n=37; major depressive disorder (MDD), n=25; acute manic episode of bipolar disorder, n=12; panic disorder, n=12, attention deficit/hyperactivity disorder (ADHD), n=20) and healthy controls (n=40) underwent an functional magnetic resonance imaging (fMRI) experiment with affectively positive, aversive and neutral pictures from the International Affective Picture System (IAPS). Between-group differences were assessed with full-factorial ANOVAs, with age, gender and smoking habits as covariates. Self-ratings of depressed mood and anxiety were correlated with activation clusters showing significant stimulus-evoked fMRI activation. Furthermore, we examined functional connectivity with the amygdala as seed region during the processing of aversive pictures. During the presentation of pleasant stimuli, we observed across all subjects significant activation of the ventromedial prefrontal cortex (vmPFC), bilateral middle temporal gyrus and right precuneus, while a significant activation of the left amygdala and the bilateral middle temporal gyrus was found during the presentation of aversive stimuli. We did neither find any significant interaction with diagnostic group, nor any correlation with depression and anxiety scores at the activated clusters or with amygdala connectivity. Positive and aversive IAPS-stimuli were consistently processed in limbic and prefrontal brain areas, irrespective of diagnostic category. A dimensional correlate of these neural activation patterns was not found.

Facing the fear--clinical and neural effects of cognitive behavioural and pharmacotherapy in panic disorder with agoraphobia.

INTRODUCTION: Cognitive behavioural therapy (CBT) and pharmacological treatment with selective serotonin or serotonin-noradrenalin reuptake inhibitors (SSRI/SSNRI) are regarded as efficacious treatments for panic disorder with agoraphobia (PD/AG). However, little is known about treatment-specific effects on symptoms and neurofunctional correlates. EXPERIMENTAL PROCEDURES: We used a comparative design with PD/AG patients receiving either two types of CBT (therapist-guided (n=29) or non-guided exposure (n=22)) or pharmacological treatment (SSRI/SSNRI; n=28) as well as a wait-list control group (WL; n=15) to investigate differential treatment effects in general aspects of fear and depression (Hamilton Anxiety Rating Scale HAM-A and Beck Depression Inventory BDI), disorder-specific symptoms (Mobility Inventory MI, Panic and Agoraphobia Scale subscale panic attacks PAS-panic, Anxiety Sensitivity Index ASI, rating of agoraphobic stimuli) and neurofunctional substrates during symptom provocation (Westphal-Paradigm) using functional magnetic resonance imaging (fMRI). Comparisons of neural activation patterns also included healthy controls (n=29). RESULTS: Both treatments led to a significantly greater reduction in panic attacks, depression and general anxiety than the WL group. The CBT groups, in particular, the therapist-guided arm, had a significantly greater decrease in avoidance, fear of phobic situations and anxiety symptoms and reduction in bilateral amygdala activation while the processing of agoraphobia-related pictures compared to the SSRI/SSNRI and WL groups. DISCUSSION: This study demonstrates that therapist-guided CBT leads to a more pronounced short-term impact on agoraphobic psychopathology and supports the assumption of the amygdala as a central structure in a complex fear processing system as well as the amygdala's involvement in the fear system's sensitivity to treatment.

Neural correlates of individual differences in anxiety sensitivity: an fMRI study using semantic priming.

Individuals with high anxiety sensitivity (AS) have an increased risk of developing anxiety disorders and are more biased in how they process fear-related stimuli. This study investigates the neural correlates of fear-related words and word associations in high- and low-AS individuals. We used a semantic priming paradigm during functional magnetic resonance imaging in which three types of target words (fear symptoms, e.g. 'dizziness'; neutral, e.g. 'drink'; and pseudowords, e.g. 'salkom') were preceded by two types of prime words (fear-triggers, e.g. 'elevator'; and neutral, e.g. 'bottle'). Subjects with high AS rated fear-symptom words (vs neutral words) as more unpleasant than low-AS individuals; they also related these words more strongly to fear-triggers and showed prolonged reaction times. During the processing of fear-symptom words, greater activation in the left anterior insula was observed in high-AS subjects than in low-AS subjects. Lower activation in the left inferior frontal gyrus, angular gyrus, fusiform gyrus and bilateral amygdalae was found in high-AS subjects when fear-symptom words were preceded by fear-trigger words. The findings suggest that cognitive biases and the anterior insula play a crucial role in high-AS individuals. Furthermore, semantic processes may contribute to high AS and the risk of developing anxiety disorders.

Predicting treatment response to cognitive behavioral therapy in panic disorder with agoraphobia by integrating local neural information.

IMPORTANCE: Although neuroimaging research has made substantial progress in identifying the large-scale neural substrate of anxiety disorders, its value for clinical application lags behind expectations. Machine-learning approaches have predictive potential for individual-patient prognostic purposes and might thus aid translational efforts in psychiatric research. OBJECTIVE: To predict treatment response to cognitive behavioral therapy (CBT) on an individual-patient level based on functional magnetic resonance imaging data in patients with panic disorder with agoraphobia (PD/AG). DESIGN, SETTING, AND PARTICIPANTS: We included 49 patients free of medication for at least 4 weeks and with a primary diagnosis of PD/AG in a longitudinal study performed at 8 clinical research institutes and outpatient centers across Germany. The functional magnetic resonance imaging study was conducted between July 2007 and March 2010. INTERVENTIONS: Twelve CBT sessions conducted 2 times a week focusing on behavioral exposure. MAIN OUTCOMES AND MEASURES: Treatment response was defined as exceeding a 50% reduction in Hamilton Anxiety Rating Scale scores. Blood oxygenation level-dependent signal was measured during a differential fear-conditioning task. Regional and whole-brain gaussian process classifiers using a nested leave-one-out cross-validation were used to predict the treatment response from data acquired before CBT. RESULTS: Although no single brain region was predictive of treatment response, integrating regional classifiers based on data from the acquisition and the extinction phases of the fear-conditioning task for the whole brain yielded good predictive performance (accuracy, 82%; sensitivity, 92%; specificity, 72%; P < .001). Data from the acquisition phase enabled 73% correct individual-patient classifications (sensitivity, 80%; specificity, 67%; P < .001), whereas data from the extinction phase led to an accuracy of 74% (sensitivity, 64%; specificity, 83%; P < .001). Conservative reanalyses under consideration of potential confounders yielded nominally lower but comparable accuracy rates (acquisition phase, 70%; extinction phase, 71%; combined, 79%). CONCLUSIONS AND RELEVANCE: Predicting treatment response to CBT based on functional neuroimaging data in PD/AG is possible with high accuracy on an individual-patient level. This novel machine-learning approach brings personalized medicine within reach, directly supporting clinical decisions for the selection of treatment options, thus helping to improve response rates.

Separating depressive comorbidity from panic disorder: A combined functional magnetic resonance imaging and machine learning approach.

BACKGROUND: Depression is frequent in panic disorder (PD); yet, little is known about its influence on the neural substrates of PD. Difficulties in fear inhibition during safety signal processing have been reported as a pathophysiological feature of PD that is attenuated by depression. We investigated the impact of comorbid depression in PD with agoraphobia (AG) on the neural correlates of fear conditioning and the potential of machine learning to predict comorbidity status on the individual patient level based on neural characteristics. METHODS: Fifty-nine PD/AG patients including 26 (44%) with a comorbid depressive disorder (PD/AG+DEP) underwent functional magnetic resonance imaging (fMRI). Comorbidity status was predicted using a random undersampling tree ensemble in a leave-one-out cross-validation framework. RESULTS: PD/AG-DEP patients showed altered neural activation during safety signal processing, while +DEP patients exhibited generally decreased dorsolateral prefrontal and insular activation. Comorbidity status was correctly predicted in 79% of patients (sensitivity: 73%; specificity: 85%) based on brain activation during fear conditioning (corrected for potential confounders: accuracy: 73%; sensitivity: 77%; specificity: 70%). LIMITATIONS: No primary depressed patients were available; only medication-free patients were included. Major depression and dysthymia were collapsed (power considerations). CONCLUSIONS: Neurofunctional activation during safety signal processing differed between patients with or without comorbid depression, a finding which may explain heterogeneous results across previous studies. These findings demonstrate the relevance of comorbidity when investigating neurofunctional substrates of anxiety disorders. Predicting individual comorbidity status may translate neurofunctional data into clinically relevant information which might aid in planning individualized treatment. The study was registered with the ISRCTN: ISRCTN80046034.

Neural substrates of treatment response to cognitive-behavioral therapy in panic disorder with agoraphobia.

OBJECTIVE: Although exposure-based cognitive-behavioral therapy (CBT) is an effective treatment option for panic disorder with agoraphobia, the neural substrates of treatment response remain unknown. Evidence suggests that panic disorder with agoraphobia is characterized by dysfunctional safety signal processing. Using fear conditioning as a neurofunctional probe, the authors investigated neural baseline characteristics and neuroplastic changes after CBT that were associated with treatment outcome in patients with panic disorder with agoraphobia. METHOD: Neural correlates of fear conditioning and extinction were measured using functional MRI before and after a manualized CBT program focusing on behavioral exposure in 49 medication-free patients with a primary diagnosis of panic disorder with agoraphobia. Treatment response was defined as a reduction exceeding 50% in Hamilton Anxiety Rating Scale scores. RESULTS: At baseline, nonresponders exhibited enhanced activation in the right pregenual anterior cingulate cortex, the hippocampus, and the amygdala in response to a safety signal. While this activation pattern partly resolved in nonresponders after CBT, successful treatment was characterized by increased right hippocampal activation when processing stimulus contingencies. Treatment response was associated with an inhibitory functional coupling between the anterior cingulate cortex and the amygdala that did not change over time. CONCLUSIONS: This study identified brain activation patterns associated with treatment response in patients with panic disorder with agoraphobia. Altered safety signal processing and anterior cingulate cortex-amygdala coupling may indicate individual differences among these patients that determine the effectiveness of exposure-based CBT and associated neuroplastic changes. Findings point to brain networks by which successful CBT in this patient population is mediated.

Effect of cognitive-behavioral therapy on neural correlates of fear conditioning in panic disorder.

BACKGROUND: Learning by conditioning is a key ability of animals and humans for acquiring novel behavior necessary for survival in a changing environment. Aberrant conditioning has been considered a crucial factor in the etiology and maintenance of panic disorder with agoraphobia (PD/A). Cognitive-behavioral therapy (CBT) is an effective treatment for PD/A. However, the neural mechanisms underlying the effects of CBT on conditioning processes in PD/A are unknown. METHODS: In a randomized, controlled, multicenter clinical trial in medication-free patients with PD/A who were treated with 12 sessions of manualized CBT, functional magnetic resonance imaging (fMRI) was used during fear conditioning before and after CBT. Quality-controlled fMRI data from 42 patients and 42 healthy subjects were obtained. RESULTS: After CBT, patients compared to control subjects revealed reduced activation for the conditioned response (CS+ > CS-) in the left inferior frontal gyrus (IFG). This activation reduction was correlated with reduction in agoraphobic symptoms from t1 to t2. Patients compared to control subjects also demonstrated increased connectivity between the IFG and regions of the "fear network" (amygdalae, insulae, anterior cingulate cortex) across time. CONCLUSIONS: This study demonstrates the link between cerebral correlates of cognitive (IFG) and emotional ("fear network") processing during symptom improvement across time in PD/A. Further research along this line has promising potential to support the development and further optimization of targeted treatments.

Distinct panicogenic activity of sodium lactate and cholecystokinin tetrapeptide in patients with panic disorder.

BACKGROUND: The validity of experimentally induced panic attacks as a model to study the pathophysiology of panic disorder has been questioned. Unspecific, unpleasant and aversive effects as well as specific patterns of psychovegetative symptoms pointing to different subtypes of panic disorder patients have been observed. These findings raise the question of challenge paradigms as a valuable tool to identify different vulnerabilities in patients with panic disorder. METHODS: We compared the two most widely studied panicogenic drugs sodium lactate and cholecystokinine tetrapeptide (CCK-4) with placebo in 25 patients with panic disorder and matched healthy control subjects. Psychophysiological changes were measured using the Acute Panic Inventory (API) and visual analogue scales for anxiety and arousal. RESULTS: In patients with panic disorder 18 out of 25 experienced a sodium lactate- or a CCK-4 induced panic attack. Lactate or CCK-4 induced symptoms and induced panic attacks were only correlated in healthy controls, but not in patients with panic disorder. CONCLUSION: The mechanisms of lactate and CCK-4 induced panic attacks are distinct in panic disorder patients but not in healthy controls. Different neurobiological vulnerabilities may be uncovered by different challenges.

(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.