In anxiety disorders, the selection and assessment of treatment depend to a large extent on patient reports of somatic symptomatology. It is important, therefore to obtain a better understanding of the relationships between patient reports and actual underlying physiological activity. In general, self reports and physiological measures do not correlate very well. Among the possible reasons for this finding is that the physiological measures have been taken in laboratory settings rather than during patients' usual daily activities. The construction of an ambulatory monitoring device is proposed as a means of recording skin conductance, heart rate, respiration and activity levels while patients go about their daily life activities. In a past study we found that although correlations between self report and physiology are low, patients are able to perceive the direction of changes in physiologcial activity under stress. In another study we found that patients with high levels of autonomic arousal differ on several somatic ratings from patients with low levels. In still another study we have found that patients with high ratings of autonomic symptomatology require higher doses of alprazolam for treatment than do those with low ratings. In the proposed study, we wish to determine whether patients with high and low levels of autonomic symptomatology differ in underlying physiological activity. Two groups of patients, one with and one without high levels of sympathetic nervous system activity, will be compared by means of the ambulatory monitoring device. Specifically, 32 patients who do, and 32 who do not, present with heart palpitations and sweaty palms will wear the ambulatory monitoring device for 8 hours of recording. They will rate their symptoms throughout the day and comparisons will be made between the physiological recordings of the two groups and between the self reported symptoms and physiological recordings of two groups under different levels of perceived stress. Data from the study will allow us to determine whether patients who report different sets of symptoms differ in underlying physiological activity, and whether self reports of somatic symptoms correlate with actual physiologcial measures during patients' everyday activities.