Hyperfunction of left lateral prefrontal cortex and automatic thoughts in social anxiety disorder: A near-infrared spectroscopy study.

Background: Patients with social anxiety disorder (SAD) experience unusual fear in normal social situations. The verbal fluency task (VFT) was administered while subjects were undergoing near-infrared spectroscopy (NIRS) scanning. The purpose of VFT was to examine the functions of the frontal and temporal lobes.

Methods: Subjects included 145 drug-naïve patients with SAD and 152 healthy controls (HCs). All subjects underwent psychological testing to determine levels of anxiety and depression and to evaluate cognition.

Results: The scores of patients with SAD indicated significantly higher anxiety and depressive states than those in HCs on several measures: Leibowitz Social Anxiety Scale (LSAS), Profile of Mood States (POMS), Spielberger Anxiety Inventory (STAI), Beck Depression Inventory (BDI), and Social Adaptation Self-evaluation Scale (SASS). The patients with SAD also had higher scores on the future denial, threat prediction, self-denial, past denial, and interpersonal threat sections of the Depression and Anxiety Cognition Scale (DACS). NIRS scanning revealed hyperactivity in the left frontal cortex of patients with SAD. Threat prediction scores on DACS were negatively correlated with oxy-Hb responses in the right frontal cortex.

Limitations: Further studies with a larger sample size are required to verify our findings.

Conclusions: The results of this study demonstrate the different mechanisms of the right and left frontal cortex in situations of social anxiety disorder.