Abstract
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.
Highlights
Social Anxiety Disorder (SAD), formerly referred to as “social phobia,” is a commonly occurring and highly disabling psychiatric disorder, characterized by an extreme fear of being negatively evaluated in social or performance situations, leading to avoidance of social events or enduring them with excessive fear or anxiety [1]
We conducted a systematic search of the PubMed, Embase, and Web of Science databases for potentially eligible studies that compared gray matter volume (GMV) differences between social anxiety disorder (SAD) patients and healthy controls (HC) and were published in English up to February 2018
This study revealed directionally consistent larger cortical GMVs mainly involving the prefronto-temporo-parieto-occipital cortices, and subcortical GMV deficits of the putamen and thalamus in SAD patients with different clinical characteristics compared with HC
Summary
Social Anxiety Disorder (SAD), formerly referred to as “social phobia,” is a commonly occurring and highly disabling psychiatric disorder, characterized by an extreme fear of being negatively evaluated in social or performance situations, leading to avoidance of social events or enduring them with excessive fear or anxiety [1]. The inconsistencies of these findings may further be confounded by clinical characteristics associated with brain morphometry, such as age, comorbid depressive disorder and concomitant medications, as well as methodological heterogeneity among studies [19, 20]. Structural abnormalities in regions implicated in the processing and regulation of fear were reported in pediatric patients with anxiety disorders [21], while one meta-analysis found no significant age effect on GMVs in anxiety disorders [20]. We explored the effects of demographic and clinical variables as potential confounders, focusing in particular on the possible impact of age, comorbid depressive disorder and concomitant medication use on the regional GMVs in patients
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