Abstract
Social anxiety is a major co-occurring condition in individuals with autism spectrum disorder （ASD）; however, its neuroanatomical basis remains understudied. We examined the neuroanatomical correlates of social anxiety in adults with ASD and compared them in adults with neurotypical control （NC）. The subjects were 40 men with a Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition-Text Revision diagnosis of ASD who were recruited from among the outpatients at Showa University Karasuyama Hospital and 43 neurotypical men without any mental disorders. The subjects’ sociodemographic and clinical characteristics were collected, and the Liebowitz Social Anxiety Scale （LSAS-J）, Autism Spectrum Quotient, and Wechsler Adult Intelligence Scale （Third Edition） were administered to assess the severity of social anxiety, ASD symptoms, and intellectual profiles, respectively. Whole brain 1.5 T magnetic resonance imaging scans were performed. Voxel-based morphometry analysis was used to examine the neuroanatomical correlates of the LSAS-J scores. While the LSAS-J scores were negatively and positively correlated with the gray matter density （GMD） in the sensorimotor cortex and the left superior temporal gyrus in the ASD group, respectively, it had a negative and positive correlation with GMD in the left putamen and bilateral frontal pole, respectively, in the NC group. Adults with ASD have distinctive neuroanatomical correlates of social anxiety compared with their neurotypical counterparts, possibly because of different compensatory mechanisms for heightened social anxiety. These findings shed light on the unique nature of social anxiety in ASD; however, further studies with larger samples that perform a direct comparison between subjects with ASD and NC are warranted.
