Sympathetic activation in broadly defined generalized anxiety disorder

Abstract

The definition of generalized anxiety disorder (GAD) has been narrowed in successive editions of DSM by emphasizing intrusive worry and deemphasizing somatic symptoms of hyperarousal. We tried to determine the clinical characteristics of more broadly defined chronically anxious patients, and whether they would show physiological signs of sympathetic activation. A group whose chief complaint was frequent, unpleasant tension over at least the last six weeks for which they desired treatment, was compared with a group who described themselves as calm. Participants were assessed with structured interviews and questionnaires. Finger skin conductance, motor activity, and ambient temperature were measured for 24h. Results show that during waking and in bed at night, runs of continuous minute-by-minute skin conductance level (SCL) declines were skewed towards being shorter in the tense group than in the calm group. In addition, during waking, distributions of minute SCLs were skewed towards higher levels in the tense group, although overall mean SCL did not differ. Thus, the tense group showed a failure to periodically reduce sympathetic tone, presumably a corollary of failure to relax. We conclude that broader GAD criteria include a substantial number of chronically anxious and hyperaroused patients who do not fall within standard criteria. Such patients deserve attention by clinicians and researchers.

Figures

FIGURE 1

Distributions of mean deviations of waking run lengths of one-minute skin conductance level declines pooled across all subjects within each group. The mean run length for each subject was subtracted from each of that subject's run lengths. The relative numbers are normalized as the fraction of the total number for each subject. Bins are 1 minute. No smoothing was applied.