The Structure And Function Of Reward Network In Depression With Suicidal Ideation

Background and Objective:Depression is the most common cause of suicide in the psychiatric field.There are Studies discovering that suicidal ideation is the third most important risk factor for suicide and is present in the majority of depressed patients.In addition,depression and suicide are both associated with reward responses.However,the underlying mechanism of depression and suicide is still unclear.Therefore,the purpose of my project is to study the structural and functional changes of reward networks in depressed patients with and without suicidal ideation.Methods:60 patients with major depression（depression with suicidal ideation group 30 cases,depression without suicidal ideation group 30 cases）and 30 healthy control subjects matched with gender,age and education level of depression group were enrolled in this study from January 2021 to July 2021 in the Department of Depression disorders,Shenzhen Kangning Hospital.MRI resting state functional and structural images were collected in patients within 1 week after admission.They were evaluated HAMD,HAMA and BSI scales.Based on SPSS24.0 software,the chi-square test,rank-sum test and two-sample T-test were used to compare the general situation and clinical scales in this study.In addition,we use DPARSF5.2upgrade toolkit in DPABI software running under MATLAB R2018b environment to calculate the grey matter volume,ALFF,and function connection indicators.Then the specific values of the relevant grey matter volume ALFF and functional connection of the region of interest（ROI）were extracted by the region of interest（ROI）extraction module of DPABI software.In addition,the structural covariant connection strength between groups was calculated by partial correlation method.The above values were put into SPSS24.0 statistical software for comparative analysis of the three groups.Results:（1）In the data pretreatment stage of this project,3 subjects with depression were excluded due to head movements,and a total of 87 subjects were included in the analysis.There were no significant differences in gender,age and education level among the three groups（P>0.05）.The HAMD（t=3.585,P=0.001）and BSI（U=-6.65,P=0.000）scores of depression with suicidal ideation were higher than those of depression without suicidal ideation,and the depression with suicidal ideation group had more prior treatment history（X~2=5.292,P=0.021）.Experienced procreation was more likely to be associated with depression and suicidal ideation（X~2=3.996,P=0.046）.（2）After statistical analysis,it was found that there were differences in local mean gray matter volume between the three groups in two ROI.The first ROI was Ventral Tegmental Area（F=3.744,P=0.028）.Postmortem analysis found that there was a difference between the depression group with and without suicidal ideation（P=0.023）.The second ROI was Left Thalamus（F=4.013,P=0.022）.Post-hoc analysis found that there was a difference between the depression group with suicidal ideation and the depression group without suicidal ideation（P=0.023）.No statistical difference was found between local gray matter volume and HAMD,HAMA and BSI.（3）No statistical difference was found in structural covariance among the three groups.（4）No statistical difference was found in ALFF values of 11 ROI among the three groups.（5）After statistical analysis of three groups,three groups of functional connections were found existing statistical differences.The first group of functional connections was Left Ventral Striatum-Ventromedial Prefrontal Cortex（K=8.773,P=0.012）.Post-hoc analysis found differences between the depression group with suicidal ideation and the depression group without suicidal ideation（P=0.037）,and between the depression group with suicidal ideation and healthy controls（P=0.004）.The second group of functional connections was Left Anterior Insula-Anterior Cingulate（K=6.946,P=0.031）.Post-hoc analysis found differences only between depression without suicidal ideation and healthy controls（P=0.017）.The third group of functions connects was Right Anterior Insula-Right Anterior Insula（F=5.725,P=0.005）.Post-hoc analysis found differences between depression with suicidal ideation and healthy controls（P=0.045）and depression without suicidal ideation and healthy controls（P=0.006）.No statistical difference was found between functional connectivity based on ROI level and HAMD,HAMA and BSI.Conclusion:（1）The gray matter volume in the ventral tegmental area and left thalamus of depressed patients with suicidal ideation was smaller than depressed patients without suicidal ideation,which may be the structural basis of the functional changes of reward circuit,and thus affect the occurrence of suicidal ideation.（2）The functional connectivity values of ROI levels in the left ventral striatum,ventromedial prefrontal cortex,left and right anterior insula and anterior cingulate gyrus were all changed in patients with depression,suggesting that the local network functions of important nodes of reward network were changed in patients with depression.This may affect the reward network by altering the ability to make decisions,regulate emotions,and anticipate rewards,leading to depressive disorder symptoms and suicidal ideation.