Disrupted Cerebellar-Default Mode Network Functional Connectivity in Major Depressive Disorder With Gastrointestinal Symptoms.

Yudan Ding,Wenbin Guo,Feng Liu,Xiaoya Fu,Meiqi Yan,Yangpan Ou,Haohao Yan,Huabing Li

doi:10.3389/fncel.2022.833592

Abstract

Gastrointestinal (GI) symptoms are one of the common somatic symptoms presented in patients with major depressive disorder (MDD). Higher frequency of GI symptoms and higher GI symptom burden were linked to greater depression severity and increased risk of suicide ideation. However, few studies have explored the underlying mechanisms of GI symptoms in MDD. Based on previous studies, the cerebellar-DMN circuits may play a potentially critical role in GI symptoms comorbid with depression. Fifty-two first-episode drug-naive patients with MDD (35 with GI symptoms and 17 without GI symptoms) and 28 matched healthy controls were recruited in the current study and underwent resting-state functional magnetic resonance imaging scan. Cerebellar seed-based functional connectivity maps were established. Relative to depressed patients without GI symptoms, significantly increased cerebellar-anterior default mode network (DMN) connectivities were found in those with GI symptoms. Both increased and decreased functional connectivities were found between cerebellum and posterior DMN in patients with GI symptoms compared with those without GI symptoms and healthy controls. Moreover, the right Crus I - right superior temporal gyrus connectivity value was related to severity of GI symptoms and depression in all patients with MDD. The support vector machine analysis demonstrated a satisfactory classification accuracy (89%) of the disrupted cerebellar-DMN connectivities for correctly identifying MDD patients with GI symptoms. These results revealed the possible neural mechanisms for the involvement of cerebellar-DMN circuits in GI symptoms co-occurred with MDD.

Highlights

Major depressive disorder (MDD) is one of the most common and debilitating psychiatric disorders worldwide characterized by heterogeneous symptoms and highly variable course trajectories (Fried and Nesse, 2015)
This study focused on GI symptoms in first-episode, drugnaive patients with major depressive disorder (MDD) and preliminarily explored the resting-state cerebellar functional connectivity patterns of these patients
Our results demonstrated that patients with GI symptoms have more severe anxiety/somatization symptoms, greater weight loss, and more severe sleep disturbances than patients without GI symptoms and healthy controls

Summary

Introduction

Major depressive disorder (MDD) is one of the most common and debilitating psychiatric disorders worldwide characterized by heterogeneous symptoms and highly variable course trajectories (Fried and Nesse, 2015). According to an international study across 14 countries on five continents, 45–95% patients with MDD visiting primary care settings only reported somatic symptoms (Simon et al, 1999). It is well-acknowledged that Chinese individuals tend to express somatic symptoms and accept a physical disease diagnosis rather than admitting to having mental illness (Parker et al, 2001, 2005; Zhao et al, 2018), which hinders early diagnosis and appropriate treatment and results in aggravation of symptoms and even treatment resistance (Smith, 2014; Dunlop et al, 2020). Given the important role of somatic symptoms in clinical decision-making and prognosis of MDD, it is essential to clarify the clinical characteristics and pathophysiology of varies somatic symptoms in MDD

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