重性抑郁障碍（MDD）和双相障碍（BD）均存在情感调节功能的损害，当抑郁发作作为首发症状时，两者的鉴别诊断存在困难。国内外研究及本项目组前期研究已经证实,MDD和BD存在杏仁核-腹侧前额叶（AMY-VPFC）这一重要的情感神经环路的结构和功能异常,但目前尚无鉴别两种疾病的生物学标记。本项目拟应用多模态脑磁共振影像学和分子遗传学技术研究MDD、BD患者和健康对照组（各200例）AMY-VPFC功能连接与脑白质完整性的差异及其与EAAT相关基因多态性的关系。随访3年后将MDD组转躁狂的患者纳入BD组，将三组入组时的脑影像学数据、EAAT相关基因多态性的数据以及临床表型分别进行相关分析，以明确MDD和BD患者AMY-VPFC情感神经环路的差异及EAAT相关基因多态性对这种差异的影响，为探讨两种疾病病理生理机制以及确定诊断和有效的治疗方案提供可靠的依据。

It has difficulties in differentiating diagnosis due to both major depressive disorder (MDD) and bipolar disorder (BD) have depressive episode, especially when the first episode in BD is depression. Convergent evidence from our and other studies demonstrated that the abnormal of structure and function in the amygdala - the ventral prefrontal cortex (AMY-VPFC) emotional neural circuit in both MDD and BD. There are no biomarkers for identification of both disorders. In this proposed study, MDD and BD participants (200 subjects/group) will be recuited and the multi-modal magnetic resonance imaging and molecular genetics technology research will be applied to detect the differences of white matter integrity, function connectivity and Glutamine within AMY-VPFC circuitry, as well as EAAT polymorphism effects on these differences. Following up for 3 years, participants showed manic episode of from initial MDD group will be included in the BD group. The final analyses on the associations between multimodal imaging data, polymorphism of EAAT and clinical phenotype will be performed to identify the specific markers for both MDD and BD. Identification of genetic imaging measures to distinguish between MDD and BD may improve early identification of the disorders and dissociation between them. Increased understanding of pathophysiological differences could help target specific treatments to those most likely to benefit and aid development of new treatments.