The effects of yohimbine, an alpha 2-adrenergic receptor antagonist, on
anxiety, blood pressure, heart rate, and plasma levels of the
norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) and
cortisol were determined in 20 healthy subjects and 68 patients who had
agoraphobia with panic attacks or panic disorder. Yohimbine produced panic
attacks meeting DSM-III criteria in 37 patients and one healthy subject.
The patients reporting yohimbine-induced panic attacks had significantly
larger increases in plasma MHPG, cortisol, systolic blood pressure, and
heart rate than the healthy subjects. These findings support the hypothesis
relating high noradrenergic neuronal activity to the pathophysiology of
panic attacks in a subgroup of panic disorder patients.