Structural network changes in patients with major depression and schizophrenia treated with electroconvulsive therapy

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Electroconvulsive therapy (ECT) is a highly effective treatment for severe, treatment-resistant major depressive disorder (MDD).
• ECT is also utilized in schizophrenia (SZ) for drug-resistant cases, as an adjunct to antipsychotics, or when rapid symptom relief is necessary.
• While neuroimaging studies suggest ECT modulates medial temporal lobe and prefrontal cortical regions in MDD, its structural brain effects in SZ remain under-investigated.

Purpose of the Study:

• To investigate the impact of right-sided unilateral ECT on brain volume and structural networks in patients with MDD and SZ.
• To explore potential diagnosis-specific and transdiagnostic effects of ECT on brain structure.
• To examine the association between ECT-induced structural changes and clinical improvement.

Main Methods:

• Structural magnetic resonance imaging (MRI) was used to acquire brain data from 21 ECT-naïve patients (12 with MDD, 9 with SZ) before and after ECT.
• Twenty-one healthy controls were scanned once for comparison.
• Source-based morphometry (SBM) was employed to analyze modulations in structural brain networks pre- and post-ECT.

Main Results:

• ECT significantly impacted distinct structural networks in both MDD and SZ patients.
• A medial temporal lobe (MTL) network, including the hippocampus and parahippocampal cortex, showed a significant volume increase after ECT in both patient groups.
• This MTL network volume increase was not correlated with clinical improvement in either MDD or SZ. In SZ, a lateral prefrontal/cingulate cortical network also increased in volume post-ECT, and this change was associated with clinical improvement.

Conclusions:

• ECT induces structural network changes in both MDD and SZ, indicating both transdiagnostic and diagnosis-specific effects.
• While ECT-induced MTL network changes were observed in both conditions, they did not correlate with clinical outcomes.
• In SZ, ECT-associated structural changes in the lateral prefrontal/cingulate cortex were linked to clinical improvement, suggesting a potential mechanism for therapeutic efficacy in this population.