EFFECTS OF ELECTROCONVULSIVE-THERAPY ON PLASMA VASOPRESSIN AND OXYTOCIN

Background: Animal studies suggest that vasopressin has cognitive-enha ncing properties and oxytocin may have amnestic effects. A clinical re port suggests that the acute increase in oxytocin-associated neurophys in predicts clinical response to electroconvulsive therapy (ECT) in de pressed patients. Methods: Medication-free patients with major depress ion were randomized to receive right unilateral or bilateral ECT admin istered with electrical stimulus intensity at either just above seizur e threshold or at 150% above seizure threshold. The associations betwe en plasma vasopressin, oxytocin, ECT treatment parameters, clinical ou tcome, and cognitive effects were assessed. Results: The sample compri sed 55 patients. At the second ECT, patients receiving ECT at 150% abo ve initial seizure threshold had significantly greater increases in pl asma vasopressin than patients receiving low-dose ECT (ps < .01-.04), with no effects of electrode placement. At the second and ninth ECT tr eatments, the vasopressin or oxytocin surges were not associated with clinical improvement, seizure duration, time to orientation, or memory test performance. There were inverse trend-level associations between the acute surge in oxytocin levels at the ninth ECT and clinical resp onse, contradicting a report in the literature. Conclusions: Overall, these findings do nor support the hypothesis that diencephalic seizure propagation is central to the mechanism of action of ECT. (C) 1998 So ciety of Biological Psychiatry.