EFFECT OF BENZODIAZEPINES ON PLASMA-LEVELS OF HOMOVANILLIC-ACID IN ANXIOUS PATIENTS AND CONTROL SUBJECTS

The effects of four logarithmically increasing doses of intravenous di azepam or placebo on plasma homovanillic acid (HVA) were determined in benzodiazepine-naive patients with panic disorder (PD) or generalized anxiety disorder (GAD), and in healthy controls. Plasma HVA was measu red at baseline and 3 min after the first and fourth doses of diazepam /placebo. Mean baseline plasma HVA levels were significantly lower in PD patients compared with GAD patients and controls. Although plasma H VA levels decreased significantly with time in all groups, there was n o diazepam effect. This study suggests that low dopaminergic activity may occur in a subset of anxious patients (PD), and that diazepam does not significantly affect dopaminergic activity as measured by plasma HVA in humans.