Anxiety is commonly associated with insomnia. Social anxiety disorder is one of the most common forms of anxiety and a U.S. study of 176 college students looked into the links between social anxiety and insomnia. The researchers found that social anxiety was associated with increased insomnia symptoms, sleep dissatisfaction, sleep-related functional impairment, perception of a sleep problem to others and distress about sleep problems. The relationship between social anxiety and insomnia was mediated (influenced) by depressive symptoms which were thought to play an important role in the link between social anxiety and poor-quality sleep.
Buckner, Julia D. ... [et al] - Social anxiety and insomnia : the mediating role of depressive symptoms Depression and Anxiety 2008, 25(2), 124-130