Naloxone has no effect on hormonal responses to ECT in man.

Although there is clear evidence in other species that electroconvulsive therapy (ECT) is associated with changes in endogenous opioid activity, there are few data available for such a role in man. Since ECT leads to changes in certain hormones in man, particularly serum prolactin, it was postulated that such changes may represent an increase in endogenous opioids. Six unmedicated patients with major depressive illness were therefore administered either 4 mg i.v. of the opiate antagonist naloxone or a saline control infusion, just before successive treatments with ECT, in a double-blind, randomized crossover design. Blood was sampled at intervals for serum prolactin, growth hormone (GH), and cortisol. ECT led to a clear rise in serum prolactin, with no significant change seen in either serum GH or serum cortisol during the 20-min sampling interval. Naloxone had no significant effect on any of these changes. It is concluded that the rise in serum prolactin in response to ECT is not mediated by changes in endogenous opioid peptide activity