The dexamethasone suppression test in panic disorder and agoraphobia

Reports that imipramine and phenelzine prevent panic attacks in agoraphobia suggest the possibility that agoraphobia and/or panic disorder might be a clinical manifestation of underlying depression. To test this hypothesis, dexamethasone suppression tests (DSTs) were performed in 10 patients meeting DSM-III criteria for agoraphobia with panic attacks, 6 for panic disorder, and 4 whose diagnosis could have been either panic disorder or agoraphobia except that another axis I disorder precluded such a diagnosis. Abnormal DSTs were observed in only 3 patients and appeared to be attributable to causes other than panic attacks or agoraphobia. The results suggest that panic attacks and endogenous depression are separate disorders and that the anti-panic properties of imipramine and phenelzine are separate from their antidepressant actions.