Investigation of region-of-interest-based functional connectivity within the default mode network among adolescents with depression complicated by obesity

This study utilized resting-state functional magnetic resonance imaging (rs-fMRI) combined with default mode network (DMN) region-of-interest (ROI)-based functional connectivity (FC) analysis to examine adolescents with depression complicated by obesity. Correlation analyses were conducted between the functional connectivity of distinct brain regions in the depression-with-obesity cohort and scores from the Adolescent Self-Rating Life Events Checklist (ASLEC) to examine potential associations. This study aimed to elucidate the underlying pathogenesis of depression complicated by obesity and identify potential imaging biomarkers for early diagnosis in this population. We analysed rs-fMRI data from 37 adolescents with depression complicated by obesity (OMDD group, n = 37), 38 patients with depression (MDD group, n = 38), and 35 healthy controls (HCs group, n = 35). DMN FC was compared with whole-brain connectivity during rs-fMRI. Imaging data from the three groups were collected and analysed using one-way analysis of variance (ANOVA). Group differences in FC values were assessed, and correlations were examined between these values and clinical scale scores across patient groups. Compared with the MDD group, the OMDD group demonstrated significantly increased FC between the left parahippocampal gyrus (left PHG) and the right precuneus. Compared with the HCs, both the OMDD and MDD patients presented reduced FC between the left PHG and the left putamen, right putamen, and opercular part of the right inferior frontal gyrus. All findings were corrected using Gaussian random field (GRF) theory at a voxel-level threshold of P < 0.001 and a cluster-level threshold of P < 0.05 (minimum cluster size > 30 voxels). Analyses revealed significant negative correlations between the FC values of the right putamen in the OMDD group and the “interpersonal relationship” scores (r = − 0.373, P = 0.023). Compared with healthy controls, adolescents with depression complicated by obesity demonstrated significant alterations in functional integration within the DMN. Specifically, the OMDD group exhibited aberrant FC between the left PHG and the right precuneus. This aberrant FC may underlie the pathophysiology of this disorder. These findings offer novel insight into the neural mechanisms of depression comorbid with obesity, enhancing our understanding of its pathogenesis.