It remains unclear whether neurobiological dysfunction observed in major depressive disorder (MDD) and insomnia is an expression of common or independent bases. The present investigation sought to explore differences in heart rate variability (HRV)-a widely utilized biomarker of neurobiological functioning-among individuals with MDD, insomnia, and healthy controls, while awake and during distinct sleep stages (REM, N2), with the goal of improving our understanding of shared neurobiological factors in depression and insomnia. Participants were 73 adults who underwent home polysomnography. All N2 and REM sleep epochs with a duration greater than or equal to 5 min were identified for HRV analysis. Additionally, a single waking epoch was defined for each participant. From waking to N2 sleep, and waking to REM sleep, changes in HRV indices indicated participants experienced reductions in sympathetic arousal and increases in parasympathetic arousal. Contrary to hypotheses, however, no between group differences were observed in HRV. Though the present findings do not support the hypotheses of a shard neurobiological pathway between MDD and insomnia, more work is warranted to advance our understanding of the neurobiological bases of these common, debilitating, and frequently co-occurring psychiatric conditions, to improve early detection and identify novel intervention targets for these disorders.

中文翻译：

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重度抑郁症和失眠：利用清醒和睡眠衍生的心率变异性探索共同神经学基础的假设。

目前尚不清楚在重度抑郁症（MDD）和失眠中观察到的神经生物学功能障碍是否是共同或独立基础的表达。本研究旨在探讨重度抑郁症、失眠症患者和健康对照者在清醒时和不同睡眠阶段（REM、N2）期间心率变异性 (HRV) 的差异，心率变异性是一种广泛使用的神经生物学功能生物标志物，目标是提高我们对抑郁症和失眠症共有的神经生物学因素的理解。参与者为 73 名接受家庭多导睡眠监测的成年人。所有持续时间大于或等于 5 分钟的 N2 和 REM 睡眠时期均被确定用于 HRV 分析。此外，还为每个参与者定义了一个清醒时期。从醒来到 N2 睡眠，再到醒来到 REM 睡眠，HRV 指数的变化表明参与者的交感神经兴奋减少，副交感神经兴奋增加。然而，与假设相反，HRV 没有观察到组间差异。尽管目前的研究结果并不支持 MDD 和失眠之间存在碎片神经生物学途径的假设，但仍需要开展更多工作来加深我们对这些常见、使人衰弱且经常同时发生的精神疾病的神经生物学基础的理解，以改善早期发现和治疗。确定这些疾病的新干预目标。