Escitalopram normalizes decreased left inferior frontal gyrus activation in social anxiety disorder during...

Social anxiety disorder (SAD) is associated with negatively biased, self-focused attention in social situations. Neural correlates of self-referential processing and effects of selective serotonin reuptake inhibitors (SSRIs) on it remain, however, poorly known. Interestingly, these drugs have been shown to modify brain activation related to negative bias already before symptom relief in major depressive disorder. We hypothesized alteration in self-referential processing and modification of such alteration during short-term use of escitalopram in SAD.

Thirty-eight subjects with SAD and 20 healthy controls were recruited from the University of Helsinki and Aalto University. During baseline fMRI participants categorized positive and negative self-referential adjectives and neutral control words. The SAD group was then randomized to receive either escitalopram 10 mg per day (n = 14) or placebo (n = 17). After one week, the SAD group repeated the categorization task during fMRI.

Compared with healthy controls, the SAD group showed weaker response to negative vs. positive adjectives in the left inferior frontal gyrus (p = 0.039). Compared with placebo, this activation increased after a one-week escitalopram treatment (p = 0.042) without any significant change in the State-Trait Anxiety Inventory Y1 scores.

Relatively small sample size and drop-outs diminished statistical power.

SAD may be associated with decreased activation of the left inferior frontal gyrus to negative self-referential social cues. Escitalopram may normalize such activation. As left inferior frontal gyrus has been linked to inner speech while working on self-reflection tasks, the increased activation might relate to reappraising negative social cues.