重性抑郁障碍和双相情感障碍患者自杀行为影像学表征的相似性与特异性研究

Suicide is a significant public health issue and a major cause of death through out the world. Major depressive disorder (MDD) and bipolar disorder (BD) are two of the most common and debilitating mental disorders which are very important mental health problem and the rates of their incidence, recurrence, morbidity, mortality, and suicide are higher. They bring the serious economic burden of their families and the society. These patients are very painful. Patients with MDD and BD may have a 40% risk with suicide ideation. Patients with MDD have a 2–12% lifetime risk of committing suicide. BD is also associated with a higher risk of suicide and with worse early life stress. The association between MDD or BD and suicide has been well documented in the literature and MDD and BD are most closely associated with suicide. There is considerable evidence to suggest that the reasons of the suicidal behaviors in patients with MDD and BD are multifactorial and include biological factors. The previous studies of magnetic resonance imaging suggested suicidal behavior of MDD and BD may be associated with some abnormal changes in brain regions, however, the currently abnormal brain regions associated with suicidal behavior of MDD and BD is not very clear. MDD and BD belong to emotional disease category, so they share similar and different clinical symptoms and pathological physiological mechanism. The main goal of my study is to explore the similar and different mechanism of brain magnetic resonance imaging of suicidal behaviors in patients with MDD and BD. By this study we can achieve similarities and differences in multimodal neuroimaging biomarkers for suicidal behaviors in MDD and BD patients, and according to the homology and their specific imaging characterization to identify potential suicide risk patients with MDD and BD, and provide biological factors for suicide prevention. And we help to develop effective prevention and intervention of suicidal behaviors in patients with MDD and BD and to reduce the mortality rate of these patients. It can provide the biological factors for suicide prevention and early intervention work and reduce the suicide mortality of patients with MDD and BD.

自杀已成为全球关注的社会问题，其病理生理机制尚不明确。重性抑郁障碍（MDD）和双相情感障碍（BD）是两种自杀死亡率较高的重性精神疾病，约有40%的患者有自杀想法，两者与自杀联系最密切。研究两者的自杀行为对探索自杀的病理生理机制和降低自杀率至关重要。目前对于伴有自杀行为的MDD或BD单一疾病的影像学研究提示两者的自杀可能与脑皮质边缘系统的改变有关，既往研究（包括本课题组前期研究）结果表明MDD和BD的病理生理机制存在相似性和特异性，本研究假设两者与自杀行为相关的机制也可能存在相似性和特异性，拟同时纳入伴有自杀行为的MDD和BD患者，通过两者之间以及与没有自杀行为的两种疾病患者磁共振影像学数据的比较分析，寻找两者与自杀行为有关的相似性和各自特异的影像学表征，进而识别具有潜在自杀风险的MDD和BD患者群体，为MDD和BD患者自杀的早期预防和干预提供生物学标记，进一步降低MDD和BD的自杀率。

重性抑郁障碍（MDD）和双相情感障碍（BD）是两种具有高自杀风险的心境障碍疾病，MDD和BD的自杀行为的神经影像学机制尚不清楚，但可能与大脑的某些区域的结构和功能异常有关。本课题组研究发现：伴有自杀意念的MDD患者的前额叶（PFC）的脑灰质体积（GMV）存在异常，右侧背外侧PFC（DLPFC）和右腹外侧PFC（VLPFC）的GMV减少可能与自杀意念有关；伴有自杀未遂的MDD患者杏仁核（amygdala）和PFC的GMV以及amygdala-PFC的功能连接的异常可能与自杀未遂相关。应用扩散张量成像技术发现BD患者的胼胝体（CC）的体部和膝部的白质异性分数（FA）显著降低与其自杀意念相关；伴有自杀未遂的BD患者的PFC的GMV降低和脑低频波动幅度内在活动异常；比较既往伴有自杀未遂的MDD和BD的脑白质连接结构发现有自杀未遂史的MDD和BD患者均有双侧额枕下束、双侧钩束和CC的FA值的显著降低，但两者丘脑的FA值改变是不同的。以上的研究揭示了自杀可能存在独特的神经影像学标志，提供了以后自杀干预的潜在靶点；MDD和BD患者的自杀行为的影像学标志既有相同，同时也存在差异，这些异同特征为以后MDD和BD患者的自杀行为的诊断提供影像学依据，并为MDD和BD患者自杀行为的早期预防和干预提供生物学标记。