Effect of Stimulus Energy on Electroconvulsive Therapy-Induced Prolactin Release

This study was undertaken to examine the effect of stimulus energy on electroconvulsive therapy (ECT)-induced prolactin (PRL) release. Patients undergoing a course of right unilateral or bilateral ECT were studied during two consecutive treatments. The order of high- and low-energy ECT was counterbalanced between the two treatments. A multivariate repeated-measures analysis of variance with seizure duration within each condition (high/low energy ECT) used as a covariate showed that seizure duration was not significantly different between conditions, but was significantly related to PRL release. However, PRL increase in response to high-energy ECT was significantly higher compared with low-energy ECT. These results indicate that in addition to the previously demonstrated relationship between electrode placement and ECT-induced PRL response, PRL release also varies as a function of stimulus energy. The implications of the hypothesis that this neuroendocrine response could serve as an indication that an effective stimulus has been delivered are discussed.