NEUROENDOCRINE RESPONSES TO LABORATORY PANIC - COGNITIVE INTERVENTIONIN THE DOXAPRAM MODEL

Doxapram is a respiratory stimulant that appears to be a potent and sp ecific panicogenic agent. It also elicits an abnormal ventilatory resp onse in patients with panic. A replication study confirmed these findi ngs and demonstrated that behavioral and ventilatory responses to doxa pram were significantly modified by a psychological intervention desig ned to cognitively block panic. The replication study provided an oppo rtunity to simultaneously investigate the neuroendocrine effects of th e illness, the drug, the drug-induced panic attacks, and the cognitive intervention. Epinephrine (EPI), norepinephrine (NE), growth hormone (GH), adrenocorticotropin (ACTH), and cortisol were studied in patient s with panic and control subjects given placebo and doxapram injection s after receiving either standard instructions or a brief cognitive in tervention. Patients with panic had elevated levels of EPI, ACTH, and cortisol throughout the study. Doxapram had little or no detectable ef fects on plasma NE, GH, ACTH, and cortisol. Doxapram-induced panic att acks were not associated with elevations in NE, GH, ACTH, or cortisol. Doxapram led to a rapid and very brief rise in plasma EPI, which was small in subjects who did not panic and pronounced in patients who did panic. The cognitive intervention attenuated the EPI response to doxa pram, perhaps through its effect on panic, and modified the temporal p attern of ACTH and cortisol secretion. These results suggest that: (1) further study of catecholamine responses within the first few minutes after panic induction is needed; (2) intense panic can occur without significant activation of the hypothalamic-pituitary-adrenal axis; and (3) cognitive factors can modulate neuroendocrine activity in laborat ory studies of patients with panic. Copyright (C) 1996 Elsevier Scienc e Ltd.