VAGAL TONE IN GENERALIZED ANXIETY DISORDER AND THE EFFECTS OF AVERSIVE IMAGERY AND WORRISOME THINKING

Vagal tone was assessed in 15 generalized anxiety disorder (GAD) and 15 nonanxious control participants during initial baseline, aversive imagery related to worry topics, worrisome thinking, and final baseline. The GAD group showed significantly lower vagal tone at initial baseline and little change over experimental tasks, suggesting the possibility of chronic reduction in parasympathetic tone. Nonanxious participants, on the other hand, displayed significant decreases in vagal tone from baseline to imagery and further reductions from imagery to worrisome thinking. Participants reported greater anxiety during worry than during aversive images but also greater ease of generation and maintenance of the worrisome thoughts. The results support prior theorizing that GAD is characterized by autonomic inflexibility, that this phenomenon is partly due to deficient parasympathetic tone, and that worrisome thinking in particular causes phasic reductions in vagal tone.