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The ENIGMA group on Generalized Anxiety Disorder (ENIGMA‐Anxiety/GAD) is part of a broader effort to investigate anxiety disorders using imaging and genetic data across multiple sites worldwide. The group is actively conducting a mega‐analysis of a large number of brain structural scans. In this process, the group was confronted with many methodological challenges related to study planning and implementation, between‐country transfer of subject‐level data, quality control of a considerable amount of imaging data, and choices related to statistical methods and efficient use of resources. This report summarizes the background information and rationale for the various methodological decisions, as well as the approach taken to implement them. The goal is to document the approach and help guide other research groups working with large brain imaging data sets as they develop their own analytic pipelines for mega‐analyses. [ABSTRACT FROM AUTHOR]

Background: It has been proposed that individuals with generalized anxiety disorder (GAD) show dysfunctional computations related to approach‐avoidance decision‐making. However, few studies have examined the neural basis of this impairment, particularly in adolescents with GAD. The goal of the current study was to address this gap in the literature. Method: The study involved 51 adolescents with GAD and 51 typically developing (TD) comparison individuals matched on age (16.10 and 15.75 respective means), gender (30 F/21 M and 24 F/27 M), and IQ (103.20 and 103.18 respective means). Participants underwent functional magnetic resonance imaging during a passive avoidance task. Results: We found a significant Group‐by‐Reinforcement interaction within reward‐related brain regions including the caudate, putamen, mid cingulate/paracentral lobule, and superior and middle frontal gyrus. TD adolescents showed a greater differential response to reward versus punishment feedback within these regions relative to adolescents with GAD. In particular, this reflected reduced responses to rewards in the adolescents with GAD. There were no group differences in neural responses when making approach/avoidance responses. Conclusion: The results of this study suggest reduced differential responsiveness to reinforcement as a component of the pathophysiology seen in adolescents with GAD. This dysfunction likely underpins decision‐making impairments that may exacerbate the participants' worry. [ABSTRACT FROM AUTHOR]

Objective: Deficits in reinforcement-based decision making have been reported in generalized anxiety disorder. However, the pathophysiology of these deficits is largely unknown; published studies have mainly examined adolescents, and the integrity of core functional processes underpinning decision making remains undetermined. In particular, it is unclear whether the representation of reinforcement prediction error (PE) (the difference between received and expected reinforcement) is disrupted in generalized anxiety disorder. This study addresses these issues in adults with the disorder.Method: Forty-six unmedicated individuals with generalized anxiety disorder and 32 healthy comparison subjects group-matched on IQ, gender, and age performed a passive avoidance task while undergoing functional MRI. Data analyses were performed using a computational modeling approach.Results: Behaviorally, individuals with generalized anxiety disorder showed impaired reinforcement-based decision making. Imaging results revealed that during feedback, individuals with generalized anxiety disorder relative to healthy subjects showed a reduced correlation between PE and activity within the ventromedial prefrontal cortex, ventral striatum, and other structures implicated in decision making. In addition, individuals with generalized anxiety disorder relative to healthy participants showed a reduced correlation between punishment PEs, but not reward PEs, and activity within the left and right lentiform nucleus/putamen.Conclusions: This is the first study to identify computational impairments during decision making in generalized anxiety disorder. PE signaling is significantly disrupted in individuals with the disorder and may lead to their decision-making deficits and excessive worry about everyday problems by disrupting the online updating ("reality check") of the current relationship between the expected values of current response options and the actual received rewards and punishments. [ABSTRACT FROM AUTHOR]

Background: Generalized social phobia (GSP) and generalized anxiety disorder (GAD) are both associated with emotion dysregulation. Research implicates dorsal anterior cingulate cortex in both explicit emotion regulation (EER) and top-down attentional control (TAC). Although studies have examined these processes in GSP or GAD, no work compares findings across the two disorders or examines functioning in cases comorbid for both disorders (GSP/GAD). Here we compare the neural correlates of EER and TAC in GSP, GAD, and GSP/GAD. Methods: Medication-free adults with GSP (EER n = 19; TAC n = 18), GAD (EER n = 17; TAC n = 17), GSP/GAD (EER n = 17; TAC n = 15), and no psychopathology (EER n = 18; TAC n = 18) participated. During EER, individuals alternatively viewed and upregulated and downregulated responses to emotional pictures. During TAC, they performed an emotional Stroop task. Results: For both tasks, significant group × condition interactions emerged in dorsal anterior cingulate cortex and parietal cortices. Healthy adults showed significantly increased recruitment during emotion regulation, relative to emotion-picture viewing. GAD, GSP, and GSP/GAD subjects showed no such increases, with all groups differing from healthy adults but not from each other. Evidence of emotion-related disorder-specificity emerged in medial prefrontal cortex and amygdala. This disorder-specific responding varied as a function of emotion content but not emotion-regulatory demands. Conclusions: GSP and GAD both involve reduced capacity for engaging emotion-regulation brain networks, whether explicitly or via TAC. A reduced ability to recruit regions implicated in top-down attention might represent a general risk factor for anxiety disorders. [ABSTRACT FROM AUTHOR]

Generalized anxiety disorder (GAD) and social phobia (SP) are major anxiety disorders identified by the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). They are comorbid, overlap in symptoms, yet present with distinct features (worry in GAD and fear of embarrassment in SP). Both have also been explained in terms of conditioning-based models. However, there is little reasoning currently to believe that GAD in adulthood reflects heightened conditionability or heightened threat processing—though patients with SP may show heightened processing of social threat stimuli. Moreover, the computational architectures that maintain these disorders in adulthood are different. For GAD this may reflect the development of an inefficient “worrying” strategy of emotional regulation. For SP this appears to reflect the atypical processing of self-referential information. [ABSTRACT FROM PUBLISHER]

Background: Generalized anxiety disorder (GAD) can significantly impair quality of life and is associated with a relatively poor long‐term prognosis. Anxiety disorders are often associated with hyper‐responsiveness to threat, perhaps coupled with impaired executive functioning. However, GAD, particularly adolescent GAD, has been the focus of little functional neuroimaging work compared to other anxiety disorders. Here, we examine the neural association of adolescent GAD with responsiveness to threat and response control. Methods: The study involved 35 adolescents with GAD and 34 healthy comparison individuals (N = 69) matched on age, gender, and IQ. Participants were scanned during an affective number Stroop task. Results: We found significant Group‐by‐Task Condition interactions in regions involved in response control/motor responding (bilateral precentral gyri and cerebellum) and/or cognitive control/attention (dorsomedial and lateral frontal cortex, posterior cingulate cortex, cuneus, and precuneus). In line with predictions, the youth with GAD showed significantly less recruitment during task trials than the healthy comparison individuals. However, no indications of specific heightened responses to threat were seen. Conclusions: GAD involves reduced capacity for engaging regions involved in response control/motor responding and/or cognitive control/attention. This might reflect either a secondary consequence of the patient's worry or an early risk factor for the development of worry. [ABSTRACT FROM AUTHOR]

There is preliminary data indicating that patients with generalized anxiety disorder (GAD) show impairment on decision-making tasks requiring the appropriate representation of reinforcement value. The current study aimed to extend this literature using the passive avoidance (PA) learning task, where the participant has to learn to respond to stimuli that engender reward and avoid responding to stimuli that engender punishment. Six stimuli engendering reward and six engendering punishment are presented once per block for 10 blocks of trials. Thirty-nine medication-free patients with GAD and 29 age-, IQ and gender matched healthy comparison individuals performed the task. In addition, indexes of social functioning as assessed by the Global Assessment of Functioning (GAF) scale were obtained to allow for correlational analyzes of potential relations between cognitive and social impairments. The results revealed a Group-by-Error Type-by-Block interaction; patients with GAD committed significantly more commission (passive avoidance) errors than comparison individuals in the later blocks (blocks 7,8, and 9). In addition, the extent of impairment on these blocks was associated with their functional impairment as measured by the GAF scale. These results link GAD with anomalous decision-making and indicate that a potential problem in reinforcement representation may contribute to the severity of expression of their disorder. [ABSTRACT FROM AUTHOR]