Rumination As A Vulnerability Factor To Depressive Symptoms In Adolescents And The Neural Mechanism Of Rumination

Objective:(1) To investigate the roles of rumination, as well as stress, in the development of adolescents'depression symptoms, and construct the adolescents'rumination vulnerability-stress model. (2) To test the cross-cultural applicability of the response styles theory of depression in urban and rural samples of adolescents in China.Methods:553 high school students of Changsha in urban areas and 577 high school students of Liuyang in rural areas participated in the longitudinal study for half a year, with an interval of 1 months. All participants finished the Center for Epidemiological Studies Depression Scale, Multidimensional Anxiety Scale for Children, Response Styles Questionnaire-Rumination Subscale, NEO Five Factor Inventory-Neuroticism Subscale, and Adolescent Life Events Questionnaire at Time 1, and questionnaires assessing depression and anxiety symptoms as well as life events at each follow-up. Hierarchical Lineal Modeling (HLM) was used in data analysis.Results:(1) The test-retest reliability was 0.70(p<.001). (2) In both our urban and rural samples, after controlling for initial depressive symptoms, residual change in anxious symptoms, and neuroticism, rumination remained a significant predictor of depressive symptoms at all six follow-ups. However, after controlling for initial anxious symptoms, residual change in depressive symptoms, and neuroticism, rumination was no longer a significant predictor of anxious symptoms at any of the six follow-ups. (3) In both our urban and rural samples, both the main effect of Rumination and the Ruminationxstress interaction on adolescents' depression symptoms were significant. Only the Ruminationx stress interaction, but not the main effect of Rumination on adolescents'depression symptoms were significant.Conclusions:(1) A ruminative response style represents a relatively stable individual difference variable in Chinese adolescents. Higher rumination was associated with greater increases in depressive symptoms over time。(2)In line with a vulnerability-stress framework, in both samples, the association between the occurrence of negative events and increases in depressive symptoms over time was moderated by rumination. (3) Rumination represents a vulnerability factor that confers independent risk for depression, but not for anxiety symptoms in Chinese adolescents. rumination may only predict increases in anxious symptoms through the mediating role of depressive symptoms. (4) The results of the current study provide support for the cross-cultural applicability of the response styles theory of depression to two independent samples of adolescents in Hunan, China. Objective:Using the functional magnetic resonance imaging (fMRI), we examined the differences of regional brain spontaneous activity in resting state in depressed vs healthy participants, and explored the relationship between rumination and regional homogeneity (ReHo) or the functional connectivity in depression patients, to provide new clues and evidences for the understanding of the neuropathological mechanism in major depressive disorder.Methods:31 patients with major depressive disorder (according to DSM-IV) and 43 healthy subjects participated in the resting state-fMRI scans. The DPARSF was used to detect the homodynamic responses across the whole brain on fMRI data, and SPM was used to examine the t-test differences of ReHo between depression and control, the correlation between the rumination factor score of RSQ-SSV and the ReHo in the abnormal brain area or the functional connectivity of ROI in depression patients.Results:(1) Compared with healthy controls, decreased ReHo right medial frontal gyrus, the bilateral middle frontal gyrus, the left superior frontal gyrus and the left inferior frontal gyrus, and increased ReHo were found in depressed patients in the left fusiform gyrus, the left middle occipital gyrus, the left cuneus, the bilateral middle temporal gyrus, and the right precuneus (p<0.005, cluster> 10voxels, uncorrected). (2) Rumination was positively correlated with the ReHo in the right putamen, the right middle temporal gyrus and the right precuneus, which showed abnormally increased ReHo in the depression patient. (3) Significant positive correlations were found between the rumination and the functional connectivities between the right medial frontal gyrus and the left caudate, the right putamen and the right insula in depression patients. Significant positive correlations were also found between the rumination and the functional connectivities between the the left fusiform gyrus and the right superior temporal gyrus, the right middle temporal gyrus and the right insula in depression patients.Conclusions:(1) The distribution of brain areas with abnormal ReHo in depressed patients are is consistent with the Default Mode Network. Depression patients involved the ReHo reduction in medial frontal cortex and the ReHo elevation in the precuneus and posterior temporal cortex. (2) Rumination was correlated with the abnormal spontaneous activity in the ventral striatum and putamen in depression patients, and correlated with the functional connectivities between the medial frontal cortex and striatum, insula, and the fusiform gyrus in the depression patient. (3) Rumination was associated with the abnormality in cortex-limbic system of mood regulating circuit in depression patients, and that provide neural evidence for the production of rumination.