Dysfunction of ventrolateral prefrontal cortex underlying social anxiety disorder: A multi-channel NIRS study.

Chika Yokoyama,Yukika Nishimura,Tsukasa Sasaki,Shin Yasuda,Tadashi Umekage,Yui Kaneko,Kunio Takei,Motohiro Okada,Masaru Kinou,Naomi Hara,Ken Inoue,Masami Nishikawa,Hisashi Tanii,Hiroaki Kumano,Shin-Ichi Suzuki,Yuji Okazaki,Hisanobu Kaiya

doi:10.1016/j.nicl.2015.05.011

Abstract

Social anxiety disorder (SAD) is characterized by strong fear and anxiety during social interactions. Although ventrolateral prefrontal cortex (VLPFC) activity in response to emotional stimuli is related to pathological anxiety, little is known about the relationship between VLPFC activity and social anxiety. This study aimed to investigate whether VLPFC activity was involved in SAD and whether VLPFC activity was related to the level of social anxiety. Twenty-four drug-naïve patients with SAD and 35 healthy controls underwent near-infrared spectroscopy (NIRS) scanning while performing a verbal fluency task (VFT). Results indicated that, compared to the healthy controls, the SAD patients exhibited smaller changes of oxygenated hemoglobin (oxy-Hb) concentrations in the VLPFC during the VFT. Furthermore, the right VLPFC activation was negatively correlated with social avoidance. In contrast to the latter, the healthy controls exhibited a positive correlation between changes of oxy-Hb concentrations in the bilateral VLPFC and social fear. Our findings provide evidence for VLPFC dysfunction in SAD, and indicate that the VLPFC dysfunction may contribute to the difference between normal and abnormal social anxiety.

Highlights

Social anxiety disorder (SAD) is the most common anxiety disorder (Stein and Stein, 2008)
No significant association was found between task performance and Liebowitz Social Anxiety Scale (LSAS) scores in any group
The changes of oxygenated hemoglobin (oxy-Hb) concentration during the verbal fluency task (VFT) in 3 channels (CH5, 7, 8) were greater in the SAD group than in the HC group

Summary

Introduction

Social anxiety disorder (SAD) is the most common anxiety disorder (Stein and Stein, 2008). It is characterized by excessive fear and by avoidance of social situations. A core component of social anxiety is the fear of negative evaluation ⁎ Corresponding author at: Akasaka Clinic for Psychosomatic Medicine and Psychiatry, BIC Akasaka bldg. 6F 3-9-18 Akasaka, Minato-ku, Tokyo 107-0052, Japan. Tel.: +81 3 5575 8198; fax: +81 3 3584 3433. The lifetime prevalence of SAD has been estimated to be 12% (Kessler et al, 2005a). SAD is often co-morbid with major depressive disorder and bipolar disorder (Kessler et al, 2005b)

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