Noradrenergic function in generalized anxiety disorder: effects of yohimbine in healthy subjects and patients with generalized anxiety disorder.

There is extensive preclinical and clinical support for the hypothesis that hyperactivity of noradrenergic neuronal systems is related to the pathophysiology of some forms of human anxiety. In the present investigation, the behavioral, biochemical, and cardiovascular responses to the alpha 2-adrenergic receptor antagonist, yohimbine, was determined in 20 patients with generalized anxiety disorder (GAD) and 20 healthy subjects. The responses to yohimbine were generally similar in the two groups except there was a trend for the yohimbine-induced increase in plasma 3-methoxy-4-hydroxyphenylglycol to be less in the GAD patients. These findings contrast with previous studies of the effects of yohimbine in panic disorder patients and, thereby, support a neurobiological distinction between these two disorders.