Naloxone in the prevention of the adverse cognitive effects of ECT: a within-subject, placebo controlled study.

Electroconvulsive therapy (ECT) is a highly effective treatment for major depression, but is also associated with characteristic cognitive side effects. Several reports document that endogenous opioids and their receptors are activated by electroconvulsive shock (ECS) and that naloxone in doses sufficient to block endogenous opioid receptors may reverse ECS-induced retrograde amnesia. This placebo-controlled, randomized, within-patient study was conducted to examine the potential of naloxone, given in doses sufficient to block opioid receptors (high dose), to ameliorate acute anterograde and retrograde memory impairments following ECT. Compared to placebo and low dose naloxone, high dose naloxone administered immediately before ECT resulted in significant reductions in anterograde amnesia, and better performance on an attention task. Both low and high dose naloxone improved verbal fluency. There were no beneficial effects of high dose naloxone on retrograde amnesia, and an indication that high dose naloxone may have worsened retrograde amnesia for shape stimuli. There were no effects of high dose naloxone on seizure duration, vital signs, and subjective side effects. The study is consistent with prior research in which change in behavioral and physiological measures was produced principally by naloxone doses sufficient to block endogenous opioid receptors and offers evidence of the potential for ameliorating some adverse cognitive effects associated with ECT.