Patients with pathological degress of anxiety and panic disorder meeting DSM III criteria are evaluated using psychological, physiological, and biochemical approaches to understanding and treating this disorder. Particular attention is given to the role of the noradrenergic transmitter system as assessed by: 1) measurement of the metabolite MHPG in urine, plasma, and CSF; 2) adrenergic receptor number and function in platelets; and 3) response to the agonist clonidine. Other approaches to understanding the pathophysiology of anxiety and its potential treatment with clonidine and carbamazepine will be explored.