To identify the common and specific structural basis of bipolar depression (BD) and unipolar depression (UD) is crucial for clinical diagnosis. In this study, a total of 85 participants, including 22 BD patients, 36 UD patients, and 27 healthy controls, were enrolled. A voxel-based morphology method was used to identify the common and specific changes of the gray matter volume (GMV) to determine the structural basis. Significant differences in GMV were found among the three groups. Compared with healthy controls, UD patients showed decreased GMV in the orbital part of the left inferior frontal gyrus, whereas BD patients showed decreased GMV in the orbital part of the left middle frontal gyrus. Compared with BD, UD patients have increased GMV in the left supramarginal gyrus and middle temporal gyrus. Our results revealed different structural changes in UD and BD patients suggesting BD and UD have different neurophysiological underpinnings. Our study contributes toward the biological determination of morphometric changes, which could help to discriminate between UD and BD.

中文翻译：

---

单相和双相抑郁患者大脑的特定灰质体积变化

确定双相抑郁（BD）和单相抑郁（UD）的共同和特定结构基础对于临床诊断至关重要。本研究共纳入 85 名参与者，包括 22 名 BD 患者、36 名 UD 患者和 27 名健康对照者。使用基于体素的形态学方法来识别灰质体积（GMV）的常见和特定变化，以确定结构基础。三组之间的 GMV 存在显着差异。与健康对照组相比，UD患者左侧额下回眶部GMV降低，而BD患者左侧额中回眶部GMV降低。与BD相比，UD患者左侧缘上回和颞中回的GMV增加。我们的结果揭示了 UD 和 BD 患者的不同结构变化，表明 BD 和 UD 具有不同的神经生理学基础。我们的研究有助于形态学变化的生物学测定，这有助于区分 UD 和 BD。