Physiological blushing in social anxiety disorder patients with and without blushing complaints: two subtypes?

This study investigates whether social anxiety disorder (SAD) patients with blushing complaints show heightened physiological blushing and arousability in social situations than SAD patients without blushing complaints and healthy controls. SAD blushers (n=32), SAD non-blushers (n=34), and healthy controls (n=25) conducted two social tasks. The physiological responses cheek and forehead blood flow, cheek temperature, and skin conductance were recorded, as well as confederates-observed blushing. The SAD blushers showed more physiological blushing (cheek temperature and blood flow) than SAD non-blushers and observers detected this difference. This finding was also present in comparison to the controls, except for blood flow. For blood flow SAD blushers and controls did not differ but SAD non-blushers showed a 'suppressed response': a smaller cheek blood flow increase during the interaction and no recovery compared to the other groups. Furthermore, on skin conductance no differences between groups were observed. Discussed is to what extent SAD blushers and SAD non-blushers represent two qualitative distinct subgroups of SAD.