The effects of electroconvulsive therapy on melatonin

Although several studies have investigated the impact of various antidepressant medications on melatonin, there are no published reports addressing the effects of electroconvulsive therapy (ECT). Melatonin's major urinary metabolite, 6-sulfatoxymelatonin (6MT), was measured before and after an acute course of ECT. Fourteen subjects diagnosed with major depression who had failed prior pharmacologic therapy were enrolled. 6MT excretion was measured using an enzyme-linked immunosorbent assay test in 24 hour samples separated into daytime and nighttime components. Hamilton Rating Scale for Depression scores showed a significant improvement (p < 0.0001). Data analysis using the Wilcoxon signed rank test demonstrated a significant decrease in 24 hour 6MT post-ECT (p < 0.016) and daytime 6MT (p < 0.008). These results demonstrate an association between a therapeutic response to ECT and decrease in endogenous melatonin production.