A review about the putative mechanisms of action of electroconvulsive therapy in schizophrenia in human research

Electroconvulsive therapy (ECT) has multiple uses in psychiatry, but its mechanisms of action (MA) in patients with schizophrenia (PS) are poorly understood. We synthesize and discuss the available evidence in this regard. We conducted a search for primary human studies and systematic reviews searching MA of ECT in PS published in PubMed/Medline, SciELO, PsycInfo, and the Cochrane Library, including 24 articles. Genetic findings are scarce and inconsistent. At the molecular level, the dopaminergic and GABAergic role stands out. The increase in brain derived neurotrophic factor (BDNF) after ECT, is a predictor of positive clinical outcomes, while the change in N-acetyl aspartate levels would demonstrate a neuroprotective role for ECT. This intervention would improve inflammatory and oxidative parameters, thereby resulting in a symptomatic improvement. ECT is associated with an increase in functional connectivity in the thalamus, right putamen, prefrontal cortex and left precuneus, structures that play a role in the neural default mode network. A decrease in connectivity between the thalamus and the sensory cortex and an enhanced functional connectivity of the right thalamus to right putamen along with a clinical improvement have been reported after ECT. Moreover a volumetric increase in hippocampus and insula has been reported after ECT. These changes could be associated with the biochemical pathophysiology of schizophrenia. Most of the included studies are observational or quasi-experimental, with small sample sizes. However, they show simultaneous changes at different neurobiological levels, with a pathophysiological and clinical correlation. We propose that the research on ECT should be carried out from neurobiological dimensions, but with a clinical perspective.