Neuroendocrine and clinical effects of electroconvulsive therapy and their relationship to treatment outcome.

Two groups of variables, endocrine and clinical, have been reported to have predictive value in determining response to electroconvulsive therapy (ECT) in depressed patients. Baseline levels of oxytocin associated neurophysin (OAN) and peak OAN response to ECT may predict clinical outcome, while the presence of delusional symptoms may indicate favourable initial response to ECT. The purpose of this study was to examine the relationship between these variables on initial and longer term response over a course of ECT, using a direct measure of plasma oxytocin concentrations. A substantial and immediate increase in oxytocin was seen after the first ECT, with significantly attenuated responses after the third and fifth ECTs. Increased plasma vasopressin concentrations were seen after all ECT treatments, each response being of similar magnitude. No associations were found between either endocrine baseline levels or peak responses, and clinical outcome. Only clinical variables predicted outcome, as patients with psychotic symptoms had more rapid initial response to ECT, and patients who had relapsed 2 months after the end of ECT had significantly higher depression ratings at day 14 of treatment than treatment responders.