April 1, 1992
View Full PaperHeart Rate and Plasma Norepinephrine Responsivity to Orthostatic Challenge in Anxiety Disorders
Key Result
Patients with panic disorder had a significantly greater heart rate response to orthostatic challenge than controls, whereas those with social phobia exhibited higher plasma norepinephrine levels.
Study Design
Type
Case-Control (n=54)
Structured PICO
Does orthostatic challenge elicit different heart rate and plasma norepinephrine responses in patients with anxiety disorders compared to normal controls?
P
Population
54 participants, comprising 20 patients with panic disorder, 14 with social phobia, and 20 normal controls, evaluated for autonomic responsivity to orthostatic challenge.
E
Exposure
Orthostatic challenge
C
Comparator
Normal control subjects and comparison between different anxiety disorder subtypes (panic disorder vs. social phobia)
O
Outcome
Heart rate and plasma norepinephrine responsivity to orthostatic challengesurrogate
Different anxiety disorders, specifically panic disorder and social phobia, demonstrate distinct patterns of autonomic dysfunction in response to orthostatic challenge.
Abstract
Heart rate and plasma norepinephrine responsivity to a physiologic challenge, ie, orthostasis, were measured in 20 patients with panic disorder (PD) and 20 age- and sex-matched normal control subjects. While the two groups exhibited similar supine heart rates, patients with PD had a significantly greater heart rate response to orthostatic challenge. Plasma norepinephrine responses did not differ between patients with PD and normal control subjects. In a matched subgroup of 14 patients with PD, 14 normal control subjects, and 14 patients with social phobia, the patients with social phobia exhibited supine and upright plasma norepinephrine levels that were significantly higher than those of the other two diagnostic groups. Taken together, and in the context of findings from other studies, these preliminary observations suggest that the anxiety disorders may demonstrate differing patterns of autonomic dysfunction.