Electroconvulsive therapy (ECT) is effective against treatment-resistant psychosis, but its mechanisms remain unclear. Conventional

volumetry studies have revealed plasticity in limbic structures following ECT but with inconsistent clinical relevance, as they

potentially overlook subtle histological alterations. Our study analyzed microstructural changes in limbic structures after ECT using

MRI texture analysis and demonstrated a correlation with clinical response. 36 schizophrenia or schizoaffective patients treated with

ECT and medication, 27 patients treated with medication only, and 70 healthy controls (HCs) were included in this study. Structural

MRI data were acquired before and after ECT for the ECT group and at equivalent intervals for the medication-only group. The gray

matter volume and MRI texture, calculated from the gray level size zone matrix (GLSZM), were extracted from limbic structures.

After normalizing texture features to HC data, group-time interactions were estimated with repeated-measures mixed models.

Repeated-measures correlations between clinical variables and texture were analyzed. Volumetric group-time interactions were

observed in seven of fourteen limbic structures. Group-time interactions of the normalized GLSZM large area emphasis of the left

hippocampus and the right amygdala reached statistical significance. Changes in these texture features were correlated with

changes in psychotic symptoms in the ECT group but not in the medication-only group. These findings provide in vivo evidence

that microstructural changes in key limbic structures, hypothetically reflected by MRI texture, are associated with clinical response

to ECT for psychosis. These findings support the neuroplasticity hypothesis of ECT and highlight the hippocampus and amygdala as

potential targets for neuromodulation in psychosis.