Association between abnormal default mode network activity and suicidality in depressed adolescents.

Shuang Zhang,Jun Cao,Li Kuang,Han Zhang,Ming Ai,Shi-Jing Liu,Wo Wang,Shu-Dong Zhang,Jian-Mei Chen,Wei-Dong Fang,Su-Ya Wang

doi:10.1186/s12888-016-1047-7

Abstract

BackgroundSuicide is the second leading cause of death among 15- to 29-year-olds in China, and 60 % of suicidal patients have a history of depression. Previous brain imaging studies have shown that depression and suicide may be associated with abnormal activity in default mode network (DMN) regions. However, no study has specifically investigated the relationship between DMN functional activity and suicidal behavior in depressed individuals. Therefore, in the present study, we directly investigated features of DMN brain activity in adolescent patients with histories of depression and attempted suicide.MethodsA total of 35 sex- and age-matched suicidal depressed patients were compared with 18 non-suicidal depressed patients and 47 healthy controls. We explored functional activity changes in DMN regions that could be associated with suicidal behavior by comparing resting-state functional magnetic resonance imaging (rs-fMRI) signals using independent component analysis (ICA). Scores on six clinical scales that measure depression severity (Hamilton Depression Scale (HDRS) and Beck Depression Inventory (BDI)) and suicidal traits (Barratt Impulsiveness Scale (BIS-11), Suicide Attitude Questionnaire (SAQ), Beck Hopelessness Scale (BHS), and Scale for Suicide Ideation (SSI)) were compared in the three groups.ResultsCompared with the healthy controls, all of the evaluated depressed patients showed increased functional connectivity in select DMN regions. The suicidal patients showed increased connectivity in the left cerebellum and decreased connectivity in the right posterior cingulate cortex (PCC), whereas the non-suicidal depressed patients showed increased connectivity in the left superior frontal gyrus, left lingual gyrus and right precuneus and decreased connectivity in the left cerebellum. Compared to the non-suicidal patients, the suicidal patients showed increased connectivity in the left cerebellum and the left lingual gyrus and decreased connectivity in the right precuneus. No differences in the scores of any clinical scales were found between the suicidal and non-suicidal depressed patients.ConclusionsCollectively, our results highlight the importance of the DMN in the pathophysiology of depression and suggest that suicidal behavior in depressed adolescents may be related to abnormal functional connectivity in the DMN. In particular, abnormal connectivity in the PCC/precuneus and left cerebellum might be a predictor of suicidal behavior in depressed adolescent patients.

Highlights

Suicide is the second leading cause of death among 15- to 29-year-olds in China, and 60 % of suicidal patients have a history of depression
Post hoc analysis showed that the scores on all six scales significantly differed between the healthy controls (HCs) and the depressed patients with and without suicide history (p < 0.001), whereas no differences were found between the depressed patients with and without suicide history
Brain connectivity differences between the HCs and the depressed patients with and without suicide history Compared with the HCs, the depressed patients with and without suicide history showed increased functional connectivity in the right middle temporal gyrus (MTG), right middle occipital gyrus and left middle frontal gyrus

Summary

Introduction

Suicide is the second leading cause of death among 15- to 29-year-olds in China, and 60 % of suicidal patients have a history of depression. Previous brain imaging studies have shown that depression and suicide may be associated with abnormal activity in default mode network (DMN) regions. No study has investigated the relationship between DMN functional activity and suicidal behavior in depressed individuals. In the present study, we directly investigated features of DMN brain activity in adolescent patients with histories of depression and attempted suicide. Suicidal behavior does not need to be present for a patient to meet the criteria for major depressive disorder (MDD), a history of suicide attempts may indicate a more severe course of the disorder [5]. Previous research has found a 6-fold higher suicide risk in the offspring of patients with mood disorders who have attempted suicide relative to the offspring of patients with mood disorders who have not attempted suicide [6], suggesting that a close relationship exists between suicidal behavior and depression. Connectivity changes in the DMN have been correlated with pessimism during depressive episodes, but not with treatment response [16]

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