Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
Biol Psychiatry. 2013 Jan 15;73(2):111-8. doi: 10.1016/j.biopsych.2012.06.010. Epub 2012 Jul 10.
Differentiating bipolar disorder (BD) from recurrent unipolar depression (UD) is a major clinical challenge. Main reasons for this include the higher prevalence of depressive relative to hypo/manic symptoms during the course of BD illness and the high prevalence of subthreshold manic symptoms in both BD and UD depression. Identifying objective markers of BD might help improve accuracy in differentiating between BD and UD depression, to ultimately optimize clinical and functional outcome for all depressed individuals. Yet, only eight neuroimaging studies to date have directly compared UD and BD depressed individuals. Findings from these studies suggest more widespread abnormalities in white matter connectivity and white matter hyperintensities in BD than UD depression, habenula volume reductions in BD but not UD depression, and differential patterns of functional abnormalities in emotion regulation and attentional control neural circuitry in the two depression types. These findings suggest different pathophysiologic processes, especially in emotion regulation, reward, and attentional control neural circuitry in BD versus UD depression. This review thereby serves as a call to action to highlight the pressing need for more neuroimaging studies, using larger samples sizes, comparing BD and UD depressed individuals. These future studies should also include dimensional approaches, studies of at-risk individuals, and more novel neuroimaging approaches, such as connectivity analysis and machine learning. Ultimately, these approaches might provide biomarkers to identify individuals at future risk for BD versus UD and biological targets for more personalized treatment and new treatment developments for BD and UD depression.
区分双相情感障碍 (BD) 和复发性单相抑郁 (UD) 是一项主要的临床挑战。主要原因包括在 BD 疾病过程中抑郁症状相对于轻躁狂/躁狂症状更为常见，以及 BD 和 UD 抑郁中都存在亚阈值躁狂症状的高患病率。识别 BD 的客观标志物可能有助于提高区分 BD 和 UD 抑郁的准确性，最终优化所有抑郁个体的临床和功能结局。然而，迄今为止只有八项神经影像学研究直接比较了 UD 和 BD 抑郁患者。这些研究的结果表明，BD 抑郁患者的白质连接和白质高信号异常更为广泛，BD 抑郁患者的缰核体积减小，但 UD 抑郁患者没有，两种抑郁类型的情绪调节和注意力控制神经回路的功能异常模式也不同。这些发现表明 BD 与 UD 抑郁之间存在不同的病理生理过程，特别是在情绪调节、奖励和注意力控制神经回路中。因此，本综述呼吁采取行动，强调迫切需要进行更多的神经影像学研究，使用更大的样本量，比较 BD 和 UD 抑郁患者。这些未来的研究还应包括多维方法、高危人群的研究以及更新颖的神经影像学方法，如连接分析和机器学习。最终，这些方法可能为识别未来发生 BD 与 UD 的风险个体提供生物标志物，并为 BD 和 UD 抑郁提供生物靶点，以实现更个性化的治疗和新的治疗发展。
