Neuroanatomical deficits in drug-naïve adult patients with generalized social anxiety disorder: a voxel-based morphometry study

Functional Connectivity Alterations Associated with COVID-19-Related Sleep Problems: A Longitudinal Resting-State fMRI Study

Background

COVID-19 has led to reports of fatigue and sleep problems. Brain function changes underlying sleep problems (SP) post-COVID-19 are unclear.

Purpose

This study investigated SP-related brain functional connectivity (FC) alterations.

Patients and methods

Fifty-five COVID-19 survivors with SP (COVID_SP) and 33 without SP (COVID_NSP), matched for demographics, completed PSQI and underwent rs-fMRI at baseline and 2-month follow-up. Correlations between FC and clinical data were analyzed by Pearson correlation analysis with Gaussian random field (GRF) correction. The repeated-measures analysis of variance (R-M ANOVA) was completed to explore the interaction with time.

Results

At baseline, COVID_SP exhibited elevated FC: right precentral gyrus (PrG) with left lateral occipital cortex (LOcC)/right PrG, left inferior parietal lobule (IPL) with right superior frontal gyrus (SFG), left hippocampus with right inferior frontal gyrus (IFG). Higher FC between left hippocampus and right SFG correlated with PSQI scores. At 2-month follow-up, decreased FC implicated in emotion regulation, executive function, and memory; increased FC in semantics, attention, and auditory-visual processing. The changes in these regions are correlated with the scores of PSQI, GAD, and PHQ. The Repeated-Measures Analysis of Variance (R-M ANOVA) revealed a significant time interaction effect between sleep and various emotion scales. Moreover, the analysis of the functional connectivity between the right PrG and the right PrG as well as that between the left IPL and the right SFG also discovered a significant time interaction effect.

Conclusion

This study provides insight into the changes in brain function associated with SP after COVID-19. These changes may partially explain the development of SP, and they also changed over time.

Alterations in cortical thickness of frontoparietal regions in patients with social anxiety disorder

Although functional changes of the frontal and (para)limbic area for emotional hyper-reactivity and emotional dysregulation are well documented in social anxiety disorder (SAD), prior studies on structural changes have shown mixed results. This study aimed to identify differences in cortical thickness between SAD and healthy controls (CON). Thirty-five patients with SAD and forty-two matched CON underwent structural magnetic resonance imaging. A vertex-based whole brain and regional analyses were conducted for between-group comparison. The whole-brain analysis revealed increased cortical thickness in the left insula, left superior parietal lobule, left superior temporal gyrus, and left frontopolar cortex in patients with SAD compared to CON, as well as decreased thickness in the left superior/middle frontal gyrus and left fusiform gyrus in patients (after multiple-correction). The results from the ROI analysis did not align with these findings at the statistically significant level after multiple corrections. Changes in cortical thickness were not correlated with social anxiety symptoms. While consistent results were not obtained from different analysis methods, the results from the whole-brain analysis suggest that patients with SAD exhibit distinct neural deficits in areas involved in salience, attention, and socioemotional processing.

Individualized prediction of anxiety and depressive symptoms using gray matter volume in a non-clinical population

Machine learning is an emerging tool in clinical psychology and neuroscience for the individualized prediction of psychiatric symptoms. However, its application in non-clinical populations is still in its infancy. Given the widespread morphological changes observed in psychiatric disorders, our study applies five supervised machine learning regression algorithms-ridge regression, support vector regression, partial least squares regression, least absolute shrinkage and selection operator regression, and Elastic-Net regression-to predict anxiety and depressive symptom scores. We base these predictions on the whole-brain gray matter volume in a large non-clinical sample (n = 425). Our results demonstrate that machine learning algorithms can effectively predict individual variability in anxiety and depressive symptoms, as measured by the Mood and Anxiety Symptoms Questionnaire. The most discriminative features contributing to the prediction models were primarily located in the prefrontal-parietal, temporal, visual, and sub-cortical regions (e.g. amygdala, hippocampus, and putamen). These regions showed distinct patterns for anxious arousal and high positive affect in three of the five models (partial least squares regression, support vector regression, and ridge regression). Importantly, these predictions were consistent across genders and robust to demographic variability (e.g. age, parental education, etc.). Our findings offer critical insights into the distinct brain morphological patterns underlying specific components of anxiety and depressive symptoms, supporting the existing tripartite theory from a neuroimaging perspective.

Grey matter structural alterations in anxiety disorders: a voxel-based meta-analysis

Anxiety disorders (ADs) are a group of prevalent and destructive mental illnesses, but the current understanding of their underlying neuropathology is still unclear. Employing voxel-based morphometry (VBM), previous studies have demonstrated several common brain regions showing grey matter volume (GMV) abnormalities. However, contradictory results have been reported among these studies. Considering that different subtypes of ADs exhibit common core symptoms despite different diagnostic criteria, and previous meta-analyses have found common core GMV-altered brain regions in ADs, the present research aimed to combine the results of individual studies to identify common GMV abnormalities in ADs. Therefore, we first performed a systematic search in PubMed, Embase, and Web of Science on studies investigating GMV differences between patients with ADs and healthy controls (HCs). Then, the anisotropic effect-size signed differential mapping (AES-SDM) was applied in this meta-analysis. A total of 24 studies (including 25 data sets) were included in the current study, and 906 patients with ADs and 1003 HCs were included. Compared with the HCs, the patients with ADs showed increased GMV in the left superior parietal gyrus, right angular gyrus, left precentral gyrus, and right lingual gyrus, and decreased GMV in the bilateral insula, bilateral thalamus, left caudate, and right putamen. In conclusion, the current study has identified some abnormal GMV brain regions that are related to the pathological mechanisms of anxiety disorders. These findings could contribute to a better understanding of the underlying neuropathology of ADs.

Gray matter abnormalities in patients with major depressive disorder and social anxiety disorder: a voxel-based meta-analysis

BACKGROUND

Major depressive and social anxiety disorders have a high comorbidity rate and similar cognitive patterns. However, their unique and shared neuroanatomical characteristics have not been fully identified.

METHODS

Voxel-based morphometric studies comparing gray matter volume between patients with major depressive disorder/social anxiety disorder and healthy controls were searched using 4 electronic databases from the inception to March 2022. Stereotactic data were extracted and subsequently tested for convergence and differences using activation likelihood estimation. In addition, based on the result of the meta-analysis, behavioral analysis was performed to assess the functional roles of the regions affected by major depressive disorder and/or social anxiety disorder.

RESULTS

In total, 34 studies on major depressive disorder with 2873 participants, and 10 studies on social anxiety disorder with 1004 subjects were included. Gray matter volume conjunction analysis showed that the right parahippocampal gyrus region, especially the amygdala, was smaller in patients compared to healthy controls. The contrast analysis of major depressive disorder and social anxiety disorder revealed lower gray matter volume in the right lentiform nucleus and medial frontal gyrus in social anxiety disorder and lower gray matter volume in the left parahippocampal gyrus in major depressive disorder. Behavioral analysis showed that regions with lower gray matter volume in social anxiety disorder are strongly associated with negative emotional processes.

CONCLUSIONS

The shared and unique patterns of gray matter volume abnormalities in patients with major depressive and social anxiety disorder may be linked to the underlying neuropathogenesis of these mental illnesses and provide potential biomarkers. PROSPERO registration number: CRD42021277546.

Volume of subcortical brain regions in social anxiety disorder: mega-analytic results from 37 samples in the ENIGMA-Anxiety Working Group

There is limited convergence in neuroimaging investigations into volumes of subcortical brain regions in social anxiety disorder (SAD). The inconsistent findings may arise from variations in methodological approaches across studies, including sample selection based on age and clinical characteristics. The ENIGMA-Anxiety Working Group initiated a global mega-analysis to determine whether differences in subcortical volumes can be detected in adults and adolescents with SAD relative to healthy controls. Volumetric data from 37 international samples with 1115 SAD patients and 2775 controls were obtained from ENIGMA-standardized protocols for image segmentation and quality assurance. Linear mixed-effects analyses were adjusted for comparisons across seven subcortical regions in each hemisphere using family-wise error (FWE)-correction. Mixed-effects d effect sizes were calculated. In the full sample, SAD patients showed smaller bilateral putamen volume than controls (left: d = -0.077, pFWE = 0.037; right: d = -0.104, pFWE = 0.001), and a significant interaction between SAD and age was found for the left putamen (r = -0.034, pFWE = 0.045). Smaller bilateral putamen volumes (left: d = -0.141, pFWE < 0.001; right: d = -0.158, pFWE < 0.001) and larger bilateral pallidum volumes (left: d = 0.129, pFWE = 0.006; right: d = 0.099, pFWE = 0.046) were detected in adult SAD patients relative to controls, but no volumetric differences were apparent in adolescent SAD patients relative to controls. Comorbid anxiety disorders and age of SAD onset were additional determinants of SAD-related volumetric differences in subcortical regions. To conclude, subtle volumetric alterations in subcortical regions in SAD were detected. Heterogeneity in age and clinical characteristics may partly explain inconsistencies in previous findings. The association between alterations in subcortical volumes and SAD illness progression deserves further investigation, especially from adolescence into adulthood.

Targeting mediodorsal thalamic CB1 receptors to inhibit dextromethorphan-induced anxiety/exploratory-related behaviors in rats: The post-weaning effect of exercise and enriched environment on adulthood anxiety

Dextromethorphan (DXM) is an effective over-the-counter antitussive with an alarming increase as an abused drug for recreational purposes. Although reports of the association between DXM administration and anxiety, there are few investigations into the underlying DMX mechanisms of anxiogenic action. Thus, the present study aimed to investigate the role of the mediodorsal thalamus (MD) cannabinoid CB1 receptors (CB1Rs) in DXM-induced anxiety/exploratory-related behaviors in adult male Wistar rats. Animals were bilaterally cannulated in the MD regions. After one week, anxiety and exploratory behaviors were measured using an elevated plus-maze task (EPM) and a hole-board apparatus. Results showed that DXM (3-7 mg/kg, i. p.) dose-dependently increased anxiety-like behaviors. Intra-MD administration of ACPA (2.5-10 ng/rat), a selective CB1 receptor agonist, decreased anxiety-like effects of DXM. The blockade of MD CB1 receptors by AM-251 (40-120 ng/rat) did not affect the EPM task. However, it potentiated the anxiogenic response of an ineffective dose of DXM (3 mg/kg) in the animals. Moreover, the effect of post-weaning treadmill exercise (TEX) and enriched environment (EE) were examined in adulthood anxiety under the drug treatments. Juvenile rats were divided into TEX/EE and control groups. The TEX/EE-juvenile rats were placed on a treadmill and then exposed to EE for five weeks. Interestingly, compared to untreated animals, post-weaning TEX/EE inhibited the anxiety induced by DXM or AM-251/DXM. It can be concluded that the MD endocannabinoid system plays an essential role in the anxiogenic effect of dextromethorphan. Moreover, post-weaning exercise alongside an enriched environment may have an inhibitory effect on adulthood anxiety-like behaviors.

Pathological fear, anxiety and negative affect exhibit distinct neurostructural signatures: evidence from psychiatric neuroimaging meta-analysis

Internalizing disorders encompass anxiety, fear and depressive disorders, which exhibit overlap at both conceptual and symptom levels. Given that a neurobiological evaluation is lacking, we conducted a Seed-based D-Mapping comparative meta-analysis including coordinates as well as original statistical maps to determine common and disorder-specific gray matter volume alterations in generalized anxiety disorder (GAD), fear-related anxiety disorders (FAD, i.e., social anxiety disorder, specific phobias, panic disorder) and major depressive disorder (MDD). Results showed that GAD exhibited disorder-specific altered volumes relative to FAD including decreased volumes in left insula and lateral/medial prefrontal cortex as well as increased right putamen volume. Both GAD and MDD showed decreased prefrontal volumes compared to controls and FAD. While FAD showed less robust alterations in lingual gyrus compared to controls, this group presented intact frontal integrity. No shared structural abnormalities were found. Our study is the first to provide meta-analytic evidence for distinct neuroanatomical abnormalities underlying the pathophysiology of anxiety-, fear-related and depressive disorders. These findings may have implications for determining promising target regions for disorder-specific neuromodulation interventions (e.g. transcranial magnetic stimulation or neurofeedback).

Neural effects of a short-term virtual reality self-training program to reduce social anxiety

BACKGROUND

Social anxiety disorder (SAD) is characterized by anxiety regarding social situations, avoidance of external social stimuli, and negative self-beliefs. Virtual reality self-training (VRS) at home may be a good interim modality for reducing social fears before formal treatment. This study aimed to find neurobiological evidence for the therapeutic effect of VRS.

METHODS

Fifty-two patients with SAD were randomly assigned to a VRS or waiting list (WL) group. The VRS group received an eight-session VRS program for 2 weeks, whereas the WL group received no intervention. Clinical assessments and functional magnetic resonance imaging scanning with the distress and speech evaluation tasks were repeatedly performed at baseline and after 3 weeks.

RESULTS

The post-VRS assessment showed significantly decreased anxiety and avoidance scores, distress index, and negative evaluation index for 'self', but no change in the negative evaluation index for 'other'. Patients showed significant responses to the distress task in various regions, including both sides of the prefrontal regions, occipital regions, insula, and thalamus, and to the speech evaluation task in the bilateral anterior cingulate cortex. Among these, significant neuronal changes after VRS were observed only in the right lingual gyrus and left thalamus.

CONCLUSIONS

VRS-induced improvements in the ability to pay attention to social stimuli without avoidance and even positively modulate emotional cues are based on functional changes in the visual cortices and thalamus. Based on these short-term neuronal changes, VRS can be a first intervention option for individuals with SAD who avoid society or are reluctant to receive formal treatment.

Structural and functional deficits and couplings in the cortico-striato-thalamo-cerebellar circuitry in social anxiety disorder

Although functional and structural abnormalities in brain regions involved in the neurobiology of fear and anxiety have been observed in patients with social anxiety disorder (SAD), the findings have been heterogeneous due to small sample sizes, demographic confounders, and methodological differences. Besides, multimodal neuroimaging studies on structural-functional deficits and couplings are rather scarce. Herein, we aimed to explore functional network anomalies in brain regions with structural deficits and the effects of structure-function couplings on the SAD diagnosis. High-resolution structural magnetic resonance imaging (MRI) and resting-state functional MRI images were obtained from 49 non-comorbid patients with SAD and 53 demography-matched healthy controls. Whole-brain voxel-based morphometry analysis was conducted to investigate structural alterations, which were subsequently used as seeds for the resting-state functional connectivity analysis. In addition, correlation and mediation analyses were performed to probe the potential roles of structural-functional deficits in SAD diagnosis. SAD patients had significant gray matter volume reductions in the bilateral putamen, right thalamus, and left parahippocampus. Besides, patients with SAD demonstrated widespread resting-state dysconnectivity in cortico-striato-thalamo-cerebellar circuitry. Moreover, dysconnectivity of the putamen with the cerebellum and the right thalamus with the middle temporal gyrus/supplementary motor area partially mediated the effects of putamen/thalamus atrophy on the SAD diagnosis. Our findings provide preliminary evidence for the involvement of structural and functional deficits in cortico-striato-thalamo-cerebellar circuitry in SAD, and may contribute to clarifying the underlying mechanisms of structure-function couplings for SAD. Therefore, they could offer insights into the neurobiological substrates of SAD.

Structural brain correlates in major depression, anxiety disorders and post-traumatic stress disorder: A voxel-based morphometry meta-analysis

The high comorbidity of Major Depressive Disorder (MDD), Anxiety Disorders (ANX), and Posttraumatic Stress Disorder (PTSD) has hindered the study of their structural neural correlates. The authors analyzed specific and common grey matter volume (GMV) characteristics by comparing them with healthy controls (HC). The meta-analysis of voxel-based morphometry (VBM) studies showed unique GMV diminutions for each disorder (p < 0.05, corrected) and less robust smaller GMV across diagnostics (p < 0.01, uncorrected). Pairwise comparison between the disorders showed GMV differences in MDD versus ANX and in ANX versus PTSD. These results endorse the hypothesis that unique clinical features characterizing MDD, ANX, and PTSD are also reflected by disorder specific GMV correlates.

Altered gray matter volume and structural co-variance in adolescents with social anxiety disorder: evidence for a delayed and unsynchronized development of the fronto-limbic system

BACKGROUND

Social anxiety disorder (SAD) is a prevalent mental disorder diagnosed in childhood and adolescence. Theories regarding brain development and SAD suggest a close link between neurodevelopmental dysfunction at the adolescent juncture and SAD, but direct evidence is rare. This study aims to examine brain structural abnormalities in adolescents with SAD.

METHODS

High-resolution T1-weighted images were obtained from 31 adolescents with SAD (15-17 years) and 42 matching healthy controls (HC). We evaluated symptom severity with the Social Anxiety Scale for Children (SASC) and the Screen for Child Anxiety Related Emotional Disorders (SCARED). We used voxel-based morphometry analysis to detect regional gray matter volume abnormalities and structural co-variance analysis to investigate inter-regional coordination patterns.

RESULTS

We found significantly higher gray matter volume in the orbitofrontal cortex (OFC) and the insula in adolescents with SAD compared to HC. We also observed significant co-variance of the gray matter volume between the OFC and amygdala, and the OFC and insula in HC, but these co-variance relationships diminished in SAD.

CONCLUSIONS

These findings provide the first evidence that the brain structural deficits in adolescents with SAD are not only in the core regions of the fronto-limbic system, but also represented by the diminished coordination in the development of these regions. The delayed and unsynchronized development pattern of the fronto-limbic system supports SAD as an adolescent-sensitive developmental mental disorder.

Neural basis underlying the trait of attachment anxiety and avoidance revealed by the amplitude of low-frequency fluctuations and resting-state functional connectivity

Background

Attachment theory demonstrates that early attachment experience shapes internal working models with mental representations of self and close relationships, which affects personality traits and interpersonal relationships in adulthood. Although research has focused on brain structural and functional underpinnings to disentangle attachment styles in healthy individuals, little is known about the spontaneous brain activity associated with self-reported attachment anxiety and avoidance during the resting state.

Methods

One hundred and nineteen individuals participated in the study, completing the Experience in Close Relationship scale immediately after an 8-min fMRI scanning. We used the resting-state functional magnetic resonance imaging (rs-fMRI) signal of the amplitude of low-frequency fluctuation and resting-state functional connectivity to identify attachment-related regions and networks.

Results

Consequently, attachment anxiety is closely associated with the amplitude of low-frequency fluctuations in the right posterior cingulate cortex, over-estimating emotional intensity and exaggerating outcomes. Moreover, the functional connectivity between the posterior cingulate cortex and fusiform gyrus increases detection ability for potential threat or separation information, facilitating behavior motivation. The attachment avoidance is positively correlated with the amplitude of low-frequency fluctuation in the bilateral lingual gyrus and right postcentral and negatively correlated with the bilateral orbital frontal cortex and inferior temporal gyrus. Functional connection with attachment avoidance contains critical nodes in the medial temporal lobe memory system, frontal-parietal network, social cognition, and default mode network necessary to deactivate the attachment system and inhibit attachment-related behavior.

Conclusion and implications

These findings clarify the amplitude of low-frequency fluctuation and resting-state functional connectivity neural signature of attachment style, associated with attachment strategies in attachment anxiety and attachment avoidance individuals. These findings may improve our understanding of the pathophysiology of the attachment-related disorder.

Distinct grey matter volume alterations in adult patients with panic disorder and social anxiety disorder: A systematic review and voxel-based morphometry meta-analysis

BACKGROUND

The paradox of similar diagnostic criteria but potentially different neuropathologies in panic disorder (PD) and social anxiety disorder (SAD) needs to be clarified.

METHODS

We performed a qualitative systematic review and a quantitative whole-brain voxel-based morphometry (VBM) meta-analysis with an anisotropic effect-size version of seed-based D mapping (AES-SDM) to explore whether the alterations of grey matter volume (GMV) in PD are similar to or different from those in SAD, together with potential confounding factors.

RESULTS

A total of thirty-one studies were eligible for inclusion, eighteen of which were included in the meta-analysis. Compared to the respective healthy controls (HC), qualitative and quantitative analyses revealed smaller cortical-subcortical GMVs in PD patients in brain areas including the prefrontal and temporal-parietal cortices, striatum, thalamus and brainstem, predominantly right-lateralized regions, and larger GMVs in the prefrontal and temporal-parietal-occipital cortices, and smaller striatum and thalamus in SAD patients. Quantitatively, the right inferior frontal gyrus (IFG) deficit was specifically implicated in PD patients, whereas left striatum-thalamus deficits were specific to SAD patients, without shared GMV alterations in both disorders. Sex, the severity of clinical symptoms, psychiatric comorbidity, and concomitant medication use were negatively correlated with smaller regional GMV alterations in PD patients.

CONCLUSION

PD and SAD may represent different anxiety sub-entities at the neuroanatomical phenotypes level, with different specific neurostructural deficits in the right IFG of PD patients, and the left striatum and thalamus of SAD patients. This combination of differences and specificities can potentially be used to guide the development of diagnostic biomarkers for these disorders.

Insula volumes are altered in patients with social anxiety disorder

OBJECTIVE

In the present study, we aimed at examining the volumes of the insula in more pure patients with a social anxiety disorder.

METHODS

We examined twenty-one patients with social anxiety disorder according to DSM-IV and twenty healthy controls. All patients and controls were applied to magnetic resonance imaging (MRI). Insula volumes were measured by using the manual tracing method in accordance with the standard anatomical atlases and related previous studies on insula volumes.

RESULTS

We found that the mean posterior and anterior insula volumes for both sides of patients were statistically significantly reduced compared to those of healthy control subjects.

CONCLUSION

Consequently, in the present study, we found that patients with a social anxiety disorder had reduced insula volumes compared to those of healthy control subjects. However, to get strong this finding, novel studies with a larger sample size are required.

Abnormal asymmetry of thalamic volume moderates stress from parents and anxiety symptoms in children and adolescents with social anxiety disorder

Social anxiety disorder (SAD) usually onsets in childhood or adolescence and is associated with brain development and chronic family stress during this period. As an information hub, the thalamus plays a crucial role in the development of emotion processing and stress regulation. Its structural and functional lateralization have been related to mental disorders. This study examined the age-dependent asymmetry of the thalamic volume in children and adolescents with SAD. We further examined the role of the thalamic asymmetry in moderating the relationships between parental alienation, which is a main source of familial stress for children and adolescents, and anxiety symptoms in this population. Fifty-three medication-free children and adolescents with SAD and 53 typical developing controls (age: 8-17) were included. Anxiety severity was measured using the Screen for Child Anxiety-Related Emotional Disorders (SCARED). We estimated the bilateral thalamic volume and examined diagnosis effect and age-group difference on the thalamic asymmetry. We further examined the moderation of the thalamic asymmetry on the associations between scores on the parental alienation, social phobia, and total SCARED. Compared with controls, the SAD group exhibited significantly abnormal asymmetry in thalamic volume. This asymmetry became more evident in the older age group. Furthermore, this asymmetry significantly weakened the relationships between parental attachment and total SCARED score. The asymmetry of the thalamic volume and its age-group difference provide novel evidence to support brain developmental abnormalities in children and adolescents with SAD. The findings further revealed interactions between physiological and chronic stress in children and adolescents with SAD. This article is part of the special issue on 'Stress, Addiction and Plasticity'.

Parsing differences in amygdala volume among individuals with and without social and generalized anxiety disorders across the lifespan

Structural differences in the amygdala (AMG) are implicated in anxiety and observed among individuals with generalized (GAD) and social anxiety (SAD) disorders. Findings have been mixed, perhaps because studies rarely examine differences between GAD and SAD, test comorbidity, or examine age-related differences. We tested AMG volume differences among a sample of adults and youth with/without SAD and GAD. Participants (N = 242; ages 7-60 years) completed an MRI scan, diagnostic interviews, and anxiety symptom measures. Groups were formed from diagnostic interviews: 1) Typically developing (TD; n = 91); 2) GAD (n = 53); 3) SAD (n = 35); and 4) comorbid SAD/GAD (n = 63). We used analysis of covariance with a bonferroni correction to examine group differences in AMG volume. The SAD and comorbid SAD/GAD groups exhibited increased bilateral AMG volume compared to the TD group. GAD and TD groups did not differ from each other in AMG size. The SAD, but not the comorbid SAD/GAD group, displayed greater right AMG size relative to the GAD group. SAD and comorbid SAD/GAD groups did not differ from the GAD group in left AMG volume. SAD and SAD/GAD groups did not exhibit different bilateral AMG size. Linear regression analyses demonstrated that greater social anxiety but not generalized anxiety symptom severity was associated with enlarged AMG volume. Age was not associated with AMG volume and nor did age moderate any group or symptom effects. Future longitudinal studies should examine whether larger AMG volume is a unique biomarker for SAD across the lifespan.

Dissociations in cortical thickness and surface area in non-comorbid never-treated patients with social anxiety disorder

BACKGROUND

Abnormalities of functional activation and cortical volume in brain regions involved in the neurobiology of fear and anxiety have been implicated in the pathophysiology of social anxiety disorder (SAD). However, few studies have performed separate measurements of cortical thickness (CT) and cortical surface area (CSA) which reflect different neurobiological processes. Thus, we aimed to explore the cortical morphological anomaly separately in SAD using FreeSurfer.

METHODS

High-resolution structural magnetic resonance images were obtained from 32 non-comorbid never-treated adult SAD patients and 32 demography-matched healthy controls. Cortical morphometry indices including CT and CSA were separately determined by FreeSurfer and compared between the two groups via whole-brain vertex-wise analysis, while partial correlation analysis using age and gender as covariates were conducted.

FINDINGS

The patients with SAD showed decreased CT but increased CSA near-symmetrically in the bilateral prefrontal cortex (PFC) of the dorsolateral, dorsomedial, and ventromedial subdivisions, as well as the right lateral orbitofrontal cortex; increased CSA in the left superior temporal gyrus (STG) was also observed in SAD. The CSA in the left PFC was negatively correlated with the disease duration.

INTERPRETATION

As the balloon model hypothesis suggests that the tangentially stretched cortex may cause dissociations in cortical morphometry and affect the cortical capacity for information processing, our findings of dissociated morphological alterations in the PFC and cortical expansion in the STG may reflect the morphological alterations of the functional reorganization in those regions, and highlight the important role of those structures in the pathophysiology and neurobiology of SAD.

FUNDING

This study was funded by the National Natural Science Foundation of China (Grant Nos. 31700964, 31800963, 81621003, and 81820108018).

Amygdala volume and social anxiety symptom severity: Does segmentation technique matter?

The amygdala factors prominently in neurobiological models of social anxiety (SA), yet amygdala volume findings regarding SA have been inconsistent and largely focused on case-control characterization. One source of discrepant findings could be variability in volumetric techniques. Therefore, we compared amygdala volumes derived via an automated technique (Freesurfer) against a manually corrected approach, also involving Freesurfer. Additionally, we tested whether the relationship between volume and SA symptom severity would differ across volumetric techniques. We pooled participants (n = 76) from archival studies. SA severity was assessed with the Liebowitz Social Anxiety Scale; scores ranged from non-clinical to clinical levels. Freesurfer produced significantly larger amygdalar volumes for participants with poor image quality. Even after excluding such participants, paired sample t-tests showed Freesurfer's boundaries produced significantly larger amygdalar volumes than manually corrected ones, bilaterally. Yet, intra-class correlation coefficients between the two methods were high, which suggests that Freesurfer's over-estimation of amygdala volume was systemic. Regardless of segmentation technique, volumes were not associated with SA symptom severity. Potentially, amygdala sub-regions may yield clearer patterns regarding SA symptoms. Further, our study underscores the importance of image quality for segmentation of the amygdala, and image quality may be particularly valuable when examining anatomical data for subtle inter-individual differences.

Neuroimaging depression and anxiety in essential tremor: A diffusion tensor imaging study

OBJECTIVE

Patients with essential tremor (ET) may exhibit non-motor features, including those that are neuropsychiatric. Depression and anxiety are the most common among these. This study aims to investigate the possible relationship between microstructural brain changes and symptoms of depression and anxiety in ET.

METHODS

We assessed 62 ET patients (40 women and 22 men, mean age 46.0 ± 20.4) for symptoms of depression and anxiety using the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). Thirty-two patients had severe or moderate symptoms of anxiety, and 15 patients had severe or moderate depressive symptoms. Microstructural brain changes were evaluated using diffusion tensor imaging (DTI), which was reported using fractional anisotropy (FA), mean diffusivity (MD), apparent diffusion coefficient (ADC), radial diffusivity (RD), and axial diffusivity (AD) values calculated for 17 regions of interest including the prefrontal cortex, paralimbic and limbic structures and cerebellar peduncles. We evaluated the relationship between observed changes in brain regions and symptoms of depression and anxiety.

RESULTS

Decreased left amygdala FA (p = 0.003) and increased left amygdala RD (p = 0.04) were detected in depressed vs. non-depressed ET patients. Left ventrolateral prefrontal cortex (VLPFC) FA (p = 0.02) and left precuneus FA (p = 0.02) values differed between anxious patients vs. non-anxious ET patients. BDI scores were correlated with left amygdala FA and left RD, while BAI scores were correlated with left VLPFC FA and left precuneus FA.

DISCUSSION

Our results provide evidence that symptoms of depression and anxiety could be based in structural brain changes observed in patients with ET.

On a continuum to anxiety disorders: Adolescents at parental risk for anxiety show smaller rostral anterior cingulate cortex and insula thickness

BACKGROUND

Having a parent with an anxiety disorder increases the risk of anxiety symptoms and anxiety disorders during the lifespan. Moreover, childhood and adolescence anxiety disorders and symptoms have been linked to a range of brain structure abnormalities. However, to date, no study has investigated brain anatomy in adolescents at high risk based on parental anxiety disorders and in adolescents with an anxiety disorder but without any treatment or therapy.

METHODS

Anatomical images from magnetic resonance imaging of 68 adolescents with anxiety disorders without any treatment (N = 20), at risk for anxiety because of their parents' anxiety disorders (N = 21), and comparison youths (N = 27), were analyzed using Freesurfer.

RESULTS

Compared to comparison group, smaller cortical thickness of the rostral anterior cingulate cortex and of the insula was observed in anxious and at-risk groups; smaller amygdala volume was observed in the anxious group only.

LIMITATIONS

The age range studied is large (10 to 17 years old). Moreover, this study is cross-sectional. Since adolescence is one of the biggest periods of cerebral reorganization, longitudinal follow-up of these youths would be necessary.

CONCLUSIONS

Smaller rostral anterior cingulate cortex and insula cortical thickness appear to be cerebral markers of the risk of developing an anxiety disorder in adolescence. The reduction of the amygdala volume seems to be linked to the onset of the disorder.

Thalamic shape and volume abnormalities in female patients with panic disorder

The thalamus is believed to play crucial role in processing viscero-sensory information, and regulating the activity of amygdala in patients with panic disorder (PD). Previous functional neuroimaging studies have detected abnormal activation in the thalamus in patients with PD compared with healthy control subjects (HC). Very few studies, however, have investigated for volumetric abnormalities in the thalamus in patients with PD. Furthermore, to the best of our knowledge, no previous study has investigated for shape abnormalities in the thalamus in patients with PD. Twenty-five patients with PD and 25 HC participants (all female) were recruited for the study. A voxel-wise volume comparison analysis and a vertex-wise shape analysis were conducted to evaluate structural abnormalities in the PD patients compared to HC. The patients with PD demonstrated significant gray matter volume reductions in the thalamus bilaterally, relative to the HC. The shape analysis detected significant inward deformation in some thalamic regions in the PD patients, including the anterior nucleus, mediodorsal nucleus, and pulvinar nucleus. PD patients showed shape deformations in key thalamic regions that are believed to play a role in regulating emotional and cognitive functions.

Subcortical brain volumes, cortical thickness and cortical surface area in families genetically enriched for social anxiety disorder - A multiplex multigenerational neuroimaging study

BACKGROUND

Social anxiety disorder (SAD) is a disabling psychiatric condition with a genetic background. Brain alterations in gray matter (GM) related to SAD have been previously reported, but it remains to be elucidated whether GM measures are candidate endophenotypes of SAD. Endophenotypes are measurable characteristics on the causal pathway from genotype to phenotype, providing insight in genetically-based disease mechanisms. Based on a review of existing evidence, we examined whether GM characteristics meet two endophenotype criteria, using data from a unique sample of SAD-patients and their family-members of two generations. First, we investigated whether GM characteristics co-segregate with social anxiety within families genetically enriched for SAD. Secondly, heritability of the GM characteristics was estimated.

METHODS

Families with a genetic predisposition for SAD participated in the Leiden Family Lab study on SAD; T1-weighted MRI brain scans were acquired (n = 110, 8 families). Subcortical volumes, cortical thickness and cortical surface area were determined for a-priori determined regions of interest (ROIs). Next, associations with social anxiety and heritabilities were estimated.

FINDINGS

Several subcortical and cortical GM characteristics, derived from frontal, parietal and temporal ROIs, co-segregated with social anxiety within families (uncorrected p-level) and showed moderate to high heritability.

INTERPRETATION

These findings provide preliminary evidence that GM characteristics of multiple ROIs, which are distributed over the brain, are candidate endophenotypes of SAD. Thereby, they shed light on the genetic vulnerability for SAD. Future research is needed to confirm these results and to link them to functional brain alterations and to genetic variations underlying these GM changes. FUND: Leiden University Research Profile 'Health, Prevention and the Human Life Cycle'.

Cerebellar Neural Circuits Involving Executive Control Network Predict Response to Group Cognitive Behavior Therapy in Social Anxiety Disorder

Some intrinsic connectivity networks including the default mode network (DMN) and executive control network (ECN) may underlie social anxiety disorder (SAD). Although the cerebellum has been implicated in the pathophysiology of SAD and several networks relevant to higher-order cognition, it remains unknown whether cerebellar areas involved in DMN and ECN exhibit altered resting-state functional connectivity (rsFC) with cortical networks in SAD. Forty-six patients with SAD and 64 healthy controls (HC) were included and submitted to the baseline resting-state functional magnetic resonance imaging (fMRI). Seventeen SAD patients who completed post-treatment clinical assessments were included after group cognitive behavior therapy (CBT). RsFC of three cerebellar subregions in both groups was assessed respectively in a voxel-wise way, and these rsFC maps were compared by two-sample t tests between groups. Whole-brain voxel-wise regression was performed to examine whether cerebellar connectivity networks can predict response to CBT. Lower rsFC circuits of cerebellar subregions compared with HC at baseline (p < 0.05, corrected by false discovery rate) were revealed. The left Crus I rsFC with dorsal medial prefrontal cortex was negatively correlated with symptom severity. The clinical assessments in SAD patients were significantly decreased after CBT. Higher pretreatment cerebellar rsFC with angular gyrus and dorsal lateral frontal cortex corresponded with greater symptom improvement following CBT. Cerebellar rsFC circuits involving DMN and ECN are possible neuropathologic mechanisms of SAD. Stronger pretreatment cerebellar rsFC circuits involving ECN suggest potential neural markers to predict CBT response.

Volumetric Associations Between Amygdala, Nucleus Accumbens, and Socially Anxious Tendencies in Healthy Women

Socially anxious individuals report higher social fears and feelings of distress in interpersonal interactions. Structural neuroimaging studies indicate brain morphological abnormalities in patients with social anxiety disorder (SAD), but findings are heterogeneous and partially discrepant. Studies on structural correlates of socially anxious tendencies in participants without clinical diagnoses are scarce. Using structural magnetic resonance imaging, the present study examined the relationship between social interaction anxiety and gray matter (GM) volume in 38 healthy women. The amygdala and nucleus accumbens (NAcc) were defined as a priori regions of interest. Moreover, exploratory whole-brain analyses were conducted. Higher levels of social anxiety significantly predicted increased GM volume in the right amygdala [k = 262 voxels, voxel-level threshold at p < .05 (uncorrected), with a cluster-corrected significance level of p = 0.05 calculated by Monte Carlo Simulations] and bilateral NAcc [left: k = 52 voxels, right: k = 49 voxels; at p < .05 (corrected for search volume)]. These relationships remained significant when controlling for a potential influence of trait anxiety. Additionally, socially anxious tendencies were associated with an enlarged striatum [i.e., putamen and caudate; left: k = 567 voxels, right: k = 539 voxels; at p < .001 (uncorrected)]. Our findings indicate that higher social interaction anxiety in healthy individuals is related to amygdalar and striatal volumetric increases. These brain regions are known to be involved in social perception, anxiety, and the avoidance of harm. Future studies may clarify whether the observed morphological alterations constitute a structural vulnerability factor for SAD.

Gray Matter Structural Alterations in Social Anxiety Disorder: A Voxel-Based Meta-Analysis

The current insight into the neurobiological pathogenesis underlying social anxiety disorder (SAD) is still rather limited. We implemented a meta-analysis to explore the neuroanatomical basis of SAD. We undertook a systematic search of studies comparing gray matter volume (GMV) differences between SAD patients and healthy controls (HC) using a whole-brain voxel-based morphometry (VBM) approach. The anisotropic effect size version of seed-based d mapping (AES-SDM) meta-analysis was conducted to explore the GMV differences of SAD patients compared with HC. We included eleven studies with 470 SAD patients and 522 HC in the current meta-analysis. In the main meta-analysis, relative to HC, SAD patients showed larger GMVs in the left precuneus, right middle occipital gyrus (MOG) and supplementary motor area (SMA), as well as smaller GMV in the left putamen. In the subgroup analyses, compared with controls, adult patients (age ≥ 18 years) with SAD exhibited larger GMVs in the left precuneus, right superior frontal gyrus (SFG), angular gyrus, middle temporal gyrus (MTG), MOG and SMA, as well as a smaller GMV in the left thalamus; SAD patients without comorbid depressive disorder exhibited larger GMVs in the left superior parietal gyrus and precuneus, right inferior temporal gyrus, fusiform gyrus, MTG and superior temporal gyrus (STG), as well as a smaller GMV in the bilateral thalami; and currently drug-free patients with SAD exhibited a smaller GMV in the left thalamus compared with HC while no larger GMVs were found. For SAD patients with different clinical features, our study revealed directionally consistent larger cortical GMVs and smaller subcortical GMVs, including locationally consistent larger precuneus and thalamic deficits in the left brain. Age, comorbid depressive disorder and concomitant medication use of the patients might be potential confounders of SAD at the neuroanatomical level.

Smaller amygdala volume and increased neuroticism predict anxiety symptoms in healthy subjects: A volumetric approach using manual tracing

Volume reductions in the amygdala (AMY) have been found in patients with anxiety disorders, but findings are mixed in subclinical participants with high trait anxiety scores, in whom both reductions and increases in AMY volume have been identified. One potential reason for such discrepancies could be the employment of different methods to determine the AMY volume (i.e., manual tracing in psychiatric research vs. automated methods), in non-patient research. In addition to trait anxiety, smaller AMY volume has also been linked to neuroticism, a personality trait consistently linked to increased vulnerability to anxiety. However, it is not clear how AMY volume and neuroticism together may contribute to anxiety symptoms in healthy functioning. These issues were investigated in a sample of 46 healthy participants who underwent anatomical MRI scanning and completed questionnaires measuring trait anxiety and neuroticism. AMY volume was assessed using manual tracing, based on anatomical landmarks identified in each participant's anatomical image. First, smaller left AMY volume was linked to higher levels of neuroticism (p = .013) and trait anxiety (p = .024), which in turn were positively correlated with each other. Moreover, AMY volume had a significant indirect effect on trait anxiety through neuroticism (ab = - .009, 95% CI [- .019, - .002]). This effect was not bidirectional, as trait anxiety did not predict AMY volume through neuroticism. Collectively, these findings provide support for a brain-personality-symptom framework of understanding affective dysregulation, which may help inform the development of prevention and intervention paradigms targeting preservation of AMY volume and reduction of neuroticism, to protect against anxiety symptoms.

Voxel-based morphometry multi-center mega-analysis of brain structure in social anxiety disorder

Social anxiety disorder (SAD) is a prevalent and disabling mental disorder, associated with significant psychiatric co-morbidity. Previous research on structural brain alterations associated with SAD has yielded inconsistent results concerning the direction of the changes in gray matter (GM) in various brain regions, as well as on the relationship between brain structure and SAD-symptomatology. These heterogeneous findings are possibly due to limited sample sizes. Multi-site imaging offers new opportunities to investigate SAD-related alterations in brain structure in larger samples.

An international multi-center mega-analysis on the largest database of SAD structural T1-weighted 3T MRI scans to date was performed to compare GM volume of SAD-patients (n = 174) and healthy control (HC)-participants (n = 213) using voxel-based morphometry. A hypothesis-driven region of interest (ROI) approach was used, focusing on the basal ganglia, the amygdala-hippocampal complex, the prefrontal cortex, and the parietal cortex. SAD-patients had larger GM volume in the dorsal striatum when compared to HC-participants. This increase correlated positively with the severity of self-reported social anxiety symptoms. No SAD-related differences in GM volume were present in the other ROIs. Thereby, the results of this mega-analysis suggest a role for the dorsal striatum in SAD, but previously reported SAD-related changes in GM in the amygdala, hippocampus, precuneus, prefrontal cortex and parietal regions were not replicated. Our findings emphasize the importance of large sample imaging studies and the need for meta-analyses like those performed by the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium.

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Multi-center mega-analysis on gray matter (GM) in social anxiety disorder (SAD)

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Largest sample available for analysis to date: 174 SAD-patients vs 213 controls

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Larger GM volume in the right putamen in SAD-patients

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No SAD-related alterations in amygdala-hippocampal, prefrontal or parietal regions

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Results stress need for larger samples and meta-analyses - cf. ENIGMA Consortium

Gray Matter Abnormalities in Non-comorbid Medication-naive Patients with Major Depressive Disorder or Social Anxiety Disorder

Background

An overlap of clinical symptoms between major depressive disorder (MDD) and social anxiety disorder (SAD) suggests that the two disorders exhibit similar brain mechanisms. However, few studies have directly compared the brain structures of the two disorders. The aim of this study was to assess the gray matter volume (GMV) and cortical thickness alterations between non-comorbid medication-naive MDD patients and SAD patients.

Methods

High-resolution T1-weighted images were acquired from 37 non-comorbid MDD patients, 24 non-comorbid SAD patients and 41 healthy controls (HCs). Voxel-based morphometry analysis of the GMV (corrected with a false discovery rate of p < 0.001) and vertex-based analysis of cortical thickness (corrected with a clusterwise probability of p < 0.001) were performed, and group differences were compared by ANOVA followed by post hoc tests.

Outcomes

Relative to the HCs, both the MDD patients and SAD patients showed the following results: GMV reductions in the bilateral orbital frontal cortex (OFC), putamen, and thalamus; cortical thickening in the bilateral medial prefrontal cortex, posterior dorsolateral prefrontal cortex, insular cortex, left temporal pole, and right superior parietal cortex; and cortical thinning in the left lateral OFC and bilateral rostral middle frontal cortex. In addition, MDD patients specifically showed a greater thickness in the left fusiform gyrus and right lateral occipital cortex and a thinner thickness in the bilateral lingual and left cuneus. SAD patients specifically showed a thinner cortical thickness in the right precentral cortex.

Interpretation

Our results indicate that MDD and SAD share common patterns of gray matter abnormalities in the orbitofrontal-striatal-thalamic circuit, salience network and dorsal attention network. These consistent structural differences in the two patient groups may contribute to the broad spectrum of emotional, cognitive and behavioral disturbances observed in MDD patients and SAD patients. In addition, we found disorder-specific involvement of the visual processing regions in MDD and the precentral cortex in SAD. These findings provide new evidence regarding the shared and specific neuropathological mechanisms that underlie MDD and SAD.

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MDD and SAD share common gray matter abnormalities in the orbitofrontal-striatal-thalamic circuit, salience and dorsal attention network.

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MDD patients show disorder-specific involvement of the visual processing regions.

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SAD patients show disorder-specific involvement of the precentral cortex.

An overlap of clinical symptoms between major depressive disorder (MDD) and social anxiety disorder (SAD) suggests similar brain mechanisms for the two disorders. However, few studies have directly compared the brain structures of the two disorders. The aim of this study was to assess gray matter volume and cortical thickness alterations between non-comorbid medication-naive MDD patients and SAD patients. We found that MDD and SAD shared a common pattern of gray matter abnormalities in the orbitofrontal-striatal-thalamic circuit, salience network and dorsal attention network. MDD patients showed disorder-specific involvement of the visual processing regions. SAD patients showed disorder-specific involvement of the precentral cortex.

Aberrant pulvinar effective connectivity in generalized social anxiety disorder

Recent neuroimaging findings in general social anxiety disorder (gSAD) have extended our understanding of the neural mechanisms of gSAD beyond an amygdala-centric fear-based hyperactivity model to include other brain regions and networks relevant to salient cues. In particular, higher order areas compromising visual networks that process emotional and social information have been implicated. The pulvinar anchors this network and is a key regulatory node that mediates complex sensory inputs and the integration between limbic and frontal brain systems. However, the role of the pulvinar and specifically alteration of its effective connectivity with the rest of the brain has not been examined in the pathophysiology of gSAD, a disorder characterized by aberrant socio-emotional processing. The main aim of this study was to examine the pulvinar network effective connectivity in gSAD. In this study, we recruited 21 individuals with gSAD and 19 demographically matched healthy controls (HC), who performed an emotional face processing task while brain activity was recorded using functional magnetic resonance imaging (fMRI). To examine pulvinar-based network dynamics, Granger causality (GC) based effective connectivity (EC) analysis was applied on fMRI data to compare gSAD and HC. The EC analysis revealed heightened casual influential dynamics between pulvinar in higher order visual and frontal regions in gSAD. In conclusion, these preliminary data suggest a novel network-based cortico-pulvino-cortical neural mechanism in the pathophysiology of gSAD.

The underlying neurobiology of key functional domains in young people with mood and anxiety disorders: a systematic review

BACKGROUND

Mood and anxiety disorders are leading causes of disability and mortality, due largely to their onset during adolescence and young adulthood and broader impact on functioning. Key factors that are associated with disability and these disorders in young people are social and economic participation (e.g. education, employment), physical health, suicide and self-harm behaviours, and alcohol and substance use. A better understanding of the objective markers (i.e. neurobiological parameters) associated with these factors is important for the development of effective early interventions that reduce the impact of disability and illness persistence.

METHODS

We systematically reviewed the literature for neurobiological parameters (i.e. neuropsychology, neuroimaging, sleep-wake and circadian biology, neurophysiology and metabolic measures) associated with functional domains in young people (12 to 30 years) with mood and/or anxiety disorders.

RESULTS

Of the one hundred and thirty-four studies selected, 7.6 % investigated social and economic participation, 2.1 % physical health, 15.3 % suicide and self-harm behaviours, 6.9 % alcohol and substance use, whereas the majority (68.1 %) focussed on clinical syndrome.

CONCLUSIONS

Despite the predominance of studies that solely examine the clinical syndrome of young people the literature also provides evidence of distinct associations among objective measures (indexing various aspects of brain circuitry) and other functional domains. We suggest that a shift in focus towards characterising the mechanisms that underlie and/or mediate multiple functional domains will optimise personalised interventions and improve illness trajectories.

A smaller amygdala is associated with anxiety in Parkinson's disease: a combined FreeSurfer-VBM study

BACKGROUND

Up to 50% of all patients with Parkinson's disease (PD) suffer from anxiety symptoms, a much higher percentage than in the general population. This suggests that PD associated pathological alterations partly underlie these symptoms, although empirical evidence is limited.

METHODS

Here we investigated the association between anxiety symptoms measured with the Beck Anxiety Inventory (BAI) and hippocampal and amygdalar volume in 110 early-stage patients with PD. Measures of anxiety in PD are often obscured by overlap with the somatic symptoms. We therefore also used a subscale of the BAI, established by our recent factor analysis, that reflects 'psychological' anxiety symptoms and is independent of the severity of PD-related motor and autonomic symptoms. We used FreeSurfer and voxel-based morphometry for the volumetric analyses.

RESULTS

Both software packages showed a negative correlation between the 'psychological' subscale of the BAI, but not total BAI and volume of the left amygdala, independent of the severity of motor symptoms, autonomic dysfunction and dopaminergic or anxiolytic medication status.

CONCLUSIONS

These results confirm studies in non-PD samples showing lower left amygdalar volume in anxious patients. The results also indicate that the 'psychological' BAI subscale is a better reflection of neural correlates of anxiety in PD. Whether the left amygdalar volume decrease constitutes a premorbid trait, a PD-associated neurobiological susceptibility to anxiety or arises as a consequence of chronic anxiety symptoms remains to be determined by future prospective longitudinal studies. Nonetheless, we speculate that the Parkinson pathology is responsible for the reduction in amygdalar volume and the concomitant development of anxiety symptoms.

Insular Volume Reduction in Patients with Social Anxiety Disorder

Despite the fact that social anxiety disorder (SAD) is highly prevalent, there have been only a few structural imaging studies. Moreover, most of them reported about a volume reduction in amygdale, which plays a key role in the neural function of SAD. Insula is another region of interest. Its hyperactivity in regard to processing negative emotional information or interoceptive awareness has been detected in patients with SAD. Referring to these studies, we hypothesized that insular volumes might reduce in patients with SAD and made a comparison of insular volumes between 13 patients with SAD and 18 healthy controls with matched age and gender using voxel-based morphometry. As a result, we found a significant volume reduction in insula in the SAD group. Our results suggest that the patients with SAD might have an insular volume reduction apart from amygdala. Since insula plays a critical role in the pathology of SAD, more attention should be paid not only to functional study but also morphometrical study of insula.

Gray matter abnormalities in patients with social anxiety disorder: A voxel-based morphometry study

The main objective of this study was to investigate the gray matter volume (GMV) differences between the patients with social anxiety disorder (SAD) and healthy controls, using VBM analysis. A total of 27 consecutive patients (15 women and 12 men) with SAD and 27 age and sex-matched healthy control subjects were included in this study. With magnetic resonance imaging, we examined GMV differences between SAD and healthy control groups. We found that GMV in the right middle and inferior temporal, left superior parietal, left precuneus and right fusiform areas were significantly greater in patients with SAD than in healthy controls. In addition, GMV in the right inferior and middle temporal regions were positively correlated with the social avoidance and total social anxiety scores of the participants in the SAD group. Lastly, greater GMV in the left superior parietal and precuneal regions were correlated with the higher disability in the social life of the patients with SAD. Our results suggest that the regions that showed significant GMV differences between the two groups play an important role in the pathophysiology of SAD and increased GMV in these regions might reflect a pathological process of neural abnormalities in this disorder.

Neurostructural impact of co-occurring anxiety in pediatric patients with major depressive disorder: a voxel-based morphometry study

BACKGROUND

Depressive and anxiety disorders are among the most frequently occurring psychiatric conditions in children and adolescents and commonly present occur together. Co-occurring depression and anxiety is associated with increased functional impairment and suicidality compared to depression alone. Despite this, little is known regarding the neurostructural differences between anxiety disorders and major depressive disorder (MDD). Moreover, the neurophysiologic impact of the presence of anxiety in adolescents with MDD is unknown.

METHODS

Using voxel-based morphometry, gray matter volumes were compared among adolescents with MDD (and no co-morbid anxiety disorders, n=14), adolescents with MDD and co-morbid anxiety ("anxious depression," n=12), and healthy comparison subjects (n=41).

RESULTS

Patients with anxious depression exhibited decreased gray matter volumes in the dorsolateral prefrontal cortex (DLPFC) compared to patients with MDD alone. Compared to healthy subjects, adolescents with anxious depression had increased gray matter volumes in the pre- and post-central gyri.

LIMITATIONS

The current sample size was small and precluded an analysis of multiple covariates which may influence GMV.

CONCLUSIONS

Gray matter deficits in the DLPFC in youth with anxious depression compared to patients with MDD and no co-occurring anxiety may reflect the more severe psychopathology in these patients. Additionally, the distinct gray matter fingerprints of MDD and anxious depression (compared to healthy subjects) suggest differing neurophysiologic substrates for these conditions, though the etiology and longitudinal trajectory of the differences remain to be determined.

The common traits of the ACC and PFC in anxiety disorders in the DSM-5: meta-analysis of voxel-based morphometry studies

Background

The core domains of social anxiety disorder (SAD), generalized anxiety disorder (GAD), panic disorder (PD) with and without agoraphobia (GA), and specific phobia (SP) are cognitive and physical symptoms that are related to the experience of fear and anxiety. It remains unclear whether these highly comorbid conditions that constitute the anxiety disorder subgroups of the Diagnostic and Statistical Manual for Mental Disorders – Fifth Edition (DSM-5) represent distinct disorders or alternative presentations of a single underlying pathology.

Methods

A systematic search of voxel-based morphometry (VBM) studies of SAD, GAD, PD, GA, and SP was performed with an effect-size signed differential mapping (ES-SDM) meta-analysis to estimate the clusters of significant gray matter differences between patients and controls.

Results

Twenty-four studies were eligible for inclusion in the meta-analysis. Reductions in the right anterior cingulate gyrus and the left inferior frontal gyrus gray matter volumes (GMVs) were noted in patients with anxiety disorders when potential confounders, such as comorbid major depressive disorder (MDD), age, and antidepressant use were controlled for. We also demonstrated increased GMVs in the right dorsolateral prefrontal cortex (DLPFC) in comorbid depression-anxiety (CDA), drug-naïve and adult patients. Furthermore, we identified a reduced left middle temporal gyrus and right precentral gyrus in anxiety patients without comorbid MDD.

Conclusion

Our findings indicate that a reduced volume of the right ventral anterior cingulate gyrus and left inferior frontal gyrus is common in anxiety disorders and is independent of comorbid depression, medication use, and age. This generic effect supports the notion that the four types of anxiety disorders have a clear degree of overlap that may reflect shared etiological mechanisms. The results are consistent with neuroanatomical DLPFC models of physiological responses, such as worry and fear, and the importance of the ventral anterior cingulate (ACC)/medial prefrontal cortex (mPFC) in mediating anxiety symptoms.