PLASMA-CORTISOL CONCENTRATIONS PRECEDING LACTATE-INDUCED PANIC - PSYCHOLOGICAL, BIOCHEMICAL, AND PHYSIOLOGICAL CORRELATES

Background: We evaluated the role of plasma cortisol levels in determi ning sodium lactate-induced panic by reporting psychological, physiolo gical, and biochemical data collected from an extended sample of 214 s ubjects during the ''placebo'' infusion (isotonic saline solution) imm ediately preceding the lactate infusion procedure. Methods: One hundre d seventy patients with panic disorder, 101 (59%) of whom were assesse d to have panicked (P group), and 69 (41%) who were assessed not to ha ve panicked (NP group) with lactate infusion; and 44 normal healthy vo lunteer controls (1 of whom panicked with lactate infusion) were studi ed. Results: Before the lactate infusion, the P group exhibited hypoth alamic-pituitary-adrenal (HPA) axis activation (high plasma cortisol l evels) and evidence of hyperventilation (low PCO2 levels) in compariso n with NP and control groups. Self-reported fear, dyspnea, and diastol ic blood pressure were highest in the P group, intermediate in the NP group, and lowest in the control group. Within the P group, baseline f ear scores correlated inversely with PCO2 levels and positively with c ortisol levels while PCO2 levels correlated negatively with cortisol l evels. Significant predictors of lactate-induced panic were prelactate infusion fear and the interaction of high cortisol levels and low PCO 2 levels. Conclusion: Combined data suggest that synchronized elevatio ns of HPA axis activity, self-reported fear, and hyperventilation duri ng the period before lactate infusion predisposes to lactate-induced p anic.