The effect of niacin on facial blood flow in people with an elevated fear of negative evaluation.

The vasodilator niacin may provoke greater facial flushing and other symptoms of anxiety in patients with social anxiety disorder than in non-anxious controls. To determine whether this also applies in non-clinical samples, niacin (100mg) or placebo was administered double-blind to 33 young adults and flushing was investigated in relation to fear of negative evaluation (a cardinal feature of social anxiety). Increases in facial blood flow were greater in people with high than low fear of negative evaluation in the niacin condition, but were similar in both groups in the placebo condition. However, changes in pulse rate and ratings of embarrassment, anxiety, blushing and facial heat were similar in both groups in both drug conditions. These findings suggest that the facial vessels of people with a heightened fear of negative evaluation are particularly responsive to niacin under conditions of low anxiety and embarrassment.