To the Editor.—
The report by de Montigny1 that cholecystokinin-4 (CCK-4) can provoke paniclike attacks in normal subjects prompts us to report preliminary observations of responses to pentagastrin infusions in patients with panic disorder. Our interest in neuropeptides and anxiety was initially aroused by a group of endocrine clinic patients with "idiopathic flushing syndrome" who had symptoms similar to those of patients with panic disorder. Review of a previously described cohort2 of patients with flushing syndrome revealed three who met DSM-III-R criteria for panic disorder and had abnormalities in one or more neuropeptides (substance P, vasoactive intestinal peptide, somatostatin, or gastrin).We decided to look for abnormalities in endocrine responses to pentagastrin in patients with panic disorder to search for possible neuropeptide mediators of panic symptoms. Pentagastrin stimulates the release of a number of peptides from endocrine-containing tumors and can produce paniclike symptoms in some of these patients.