Increased central alpha 2-adrenoceptor sensitivity in panic disorder.

Cardiovascular responses to an intravenous challenge dose of clonidine (1.5 micrograms/kg) were measured in eight patients with DSM III panic disorder. In comparison with an age- and sex-matched control population panic patients showed significantly greater falls in systolic and diastolic blood pressure, with similar falls in heart rate. These observations support the view of a biological abnormality in panic disorder.