Background: In social anxiety disorder (SAD), the fear of being negatively evaluated by others can restrict individual everyday life, due to the anxiety caused by social interactions. How this anxiety is processed in the brain is only partly understood. We aimed to examine the correlations between subjective anxiety states and brain activity in a large sample of SAD patients, during an anxiety-provoking task.

Methods: Data were merged from three randomized clinical PET-trials investigating regional cerebral blood flow (rCBF) during a public speaking task pre- and post treatment (SSRI n = 35, placebo n = 37). All participants met diagnostical criteria for SAD. rCBF was assessed with [15O]-labeled water and state anxiety was measured using the Spielberger state anxiety scale (STAI-S). These measures where then correlated using a covariate of interest approach in Statistical Parametric Mapping (SPM2).

Results: rCBF and STAI-S scores correlated positively in the left parahippocampal gyrus and amygdala, as well as in the right premotor cortex (area 6). Negative correlations were observed in the left superior frontal gyrus, thalamus, and the right parahippocampal gyrus. Negative correlations were also found bilaterally in the cerebellum.

Conclusions: The correlations between clinical anxiety states and brain activity were noted in areas previously demonstrated to be involved in emotional regulation and motor preparedness.