Personalized functional connectivity analysis in responders and nonresponders to ketamine and electroconvulsive therapy: A case series

Abstract

Objective: Major depressive disorder is a common medical problem, frequently resistant to antidepressant treatments. We sought to describe functional connectivity correlates of response and non-response to rapid-acting antidepressants in patients with treatment-resistant depression. Methods: We performed an MRI-based, BOLD functional connectivity analysis on three patients with treatment-resistant depression, with varying degrees of response to electroconvulsive therapy (ECT) or intravenous subanesthetic ketamine. Results: Response to treatment was associated with an increase of positive correlations and increased connectivity of bilateral frontal, subcortical, right temporal and right occipital regions. Treatment nonresponse was associated with an increase in negative correlations between frontal lobes and their respective contra- and ipsilateral parietal and occipital lobes. Conclusion: Response to rapid-acting treatments was associated in this case series to increased functional connectivity, especially in homologous regions of both hemispheres. If replicated in a bigger sample, this correlate of response can provide insights into mechanisms of rapid-acting antidepressant treatment response.