Background:
Electroconvulsive therapy (ECT) is a highly effective treatment for depression but its use is limited by associated cognitive side-effects. Several theories have been proposed for the mechanisms underlying cognitive impairment with ECT: excito-toxic damage through influx of intracellular calcium or excessive glutamatergic transmission, alteration in opioid receptor density and induction of inflammatory processes (Krueger et al. 1992; Bazan et al. 2005). Several neuroprotective agents have been proposed to reduce ECT-related cognitive effects, leading to some trials in animal and human subjects.
Method:
A comprehensive literature review (PubMed, Medline) identified animal and human clinical research trials of various agents proposed to have a neuropro-tective effect on ECT-induced cognitive impairments.
Results:
Several agents have been shown to reduce memory impairment after electroconvulsive shock (ECS) in rats, for example, calcium channel blockers, opioid receptor antagonists and glucocorticoid antagonists. However, results from clinical trials in humans have been less promising. There are early suggestions that ketamine anesthesia may be associated with fewer cognitive side-effects after ECT (McDaniels et al. 2006).
Conclusions:
Strong evidence from ECS models of neuroprotective strategies have to date not been confirmed in human clinical trials. However, clinical trials have been sparse, with small sample sizes and confounding methodological issues. We propose a randomized sham-controlled study to assess the effect of several neuroprotective agents on ECT-induced cognitive impairment.
