The Neural Basis Of Personality Styles Effect On Depression

Personality traits are perceived to be stable, enduring, and important aspects of the individual that represent the coherent patterning of affect, behavior, cognition, and desires over time and space. Neuroticism and extraversion is considered to be two of the more important personality traits. Previous studies indicated that neuroticism and extraversion mediating the relation between the tendency of cognitive evaluation and depression, that is, a higher level of neuroticism was more reactive to negative stimuli, vulnerable to stress, less effective in regulating behavior, and more prone to worry and negative affect, whereas a lower level of extraversion was more easy to hide emotional and psychological problems, and thus prone to depression. With the continuous development of functional magnetic resonance imaging, a growing number of studies have found that the link between neurostructural and functional architecture and personality traits. However, previous studies focused minimally on personality styles. Currently, there are also no objective biological markers that can be used to reliably identify individuals with different personality styles.The first experiment explored the behavioral differences between the depressive patients with the control group. There are 99 patients with moderate to severe depression and 97 normal persons which gender, age, education level matched as control group subjects. Every participants complete the Eysenck Personality Questionnaire, Hamilton Depression Scale, Beck Depression Inventory, Behavioral Inhibition System and Behavioral Activation System Scale and MRI scanning(structural MRI). Two sample T test was used to analysis the behavioral data, the results found that there were no significant difference between depression group and the control group in age, gender and grade; but were significant difference in neuroticism, extraversion, BDI score and HAMD scores. Compared with control group, the depression group displayed significantly higher neuroticism, BDI scores and HAMD scores; but lower extroversion score. Then, we further use single factor analysis of variance to find the different between depression group and control group with personality styles, the result shows that there were no significant difference among the depression group with four personality styles in age, gender, education, BDI and HAMD scores, but were significantly different in neuroticism, extraversion and BAS/BIS questionnaire scores; there were no significant difference among the control group with four personality styles in age, gender, education, but were significantly different in the BDI, HAMD, neuroticism, extraversion and BAS/BIS questionnaire on each dimension scores.In the second experiment, our objective was to explored the brain structure differences in depression group and control group with the same personality styles. For structural imaging, we analysis the gray matter volume(GMV) using the method of voxel-based morphometry(VBM) for each subject. Two sample t-test analysis was performed to investigate the difference in the brain gray matter volume(GMV) between the depression group and control group. Compared with control group, the depression group displayed lower gray volume in the left superior parietal, the left fusiform, the left superior temporal gyrus, the left inferior frontal gyrus, the right precentral and the left cingulate. The recruited 99 patients with depression and 97 normal people in accordance with the scores of eysenck personality questionnaire were divided into four types of personality styles. Analysis of variance was performed to investigate the difference in the brain gray matter volume(GMV) between the depression group and control group with the same personality styles. Results found there were significant difference on gray volume in the left superior parietal and the left fusiform between depression group and control group with N+E+ and N-E-; there were significant difference on gray volume in the left superior temporal and the left cingulate between depression group and control group with N+E- and N-E+; there were significant difference on gray volume in the left inferior frontal gyrus between depression group and control group with N+E+ and N+E-; there were significant difference on gray volume in the right precentral between depression group and control group with N+E+, N+E- and N-E+. In addition, successful discrimination in the depression group and control group was driven by neuroanatomical alterations which were result in first study.In the third experiment, our objective was to use the SVM to develop an algorithm that distinguished depression group and control group with the same personality styles at an individual level. Found that the mask based on interest brain regions has high sensitivity and accuracy on the prediction between four personality styles. The contribution rate of brain areas further analysis found that the higher contribution brain areas between depression group and control group in N+E+ including the superior parietal, fusiform and the inferior frontal gyrus; the higher contribution brain areas between depression group and control group in N+E- including the superior temporal gyrus, the inferior frontal gyrus and the cingulum; the higher contribution brain areas between depression group and control group in N-E+ including the superior parietal, the precentral and the cingulum; the higher contribution brain areas between depression group and control group in N-E- including the fusiform.This study combined the VBM and multivariate methods to investigate the neural basis of personality types associated with depression and predict the features of the brain structure in different group with the same personality styles. Combining the results of three study, we found that the depression group displayed lower gray volume in the left superior parietal, the left fusiform, the left superior temporal gyrus, the left inferior frontal gyrus, the right precentral and the left cingulate. Besides, successful discrimination in the depression group and control group was driven by neuroanatomical alterations based on this result in first study. Overall, our findings provide a new direction for the research and evidence theory of personality, also provides a physical basis for the negative personality styles grow into depression. These findings indicated that personality styles that consider person-centered traits may be more important and effective to predict individuals’ mental health, and these results would provide a potential brain biomarker for early individual psychological risk assessments.