Minaeva O, Riese H, Booij S H, Lamers F, Giltay E J, Scheer F A J L, Hu K
Department of Psychiatry, University of Groningen, University Medical Center Groningen, Interdisciplinary Center Psychopathology and Emotion regulation, Groningen, The Netherlands.
Lentis, Center for Integrative Psychiatry, Groningen, The Netherlands.
Psychol Med. 2024 Dec 2;54(15):1-9. doi: 10.1017/S0033291724002769.
Motor activity fluctuations in healthy adults exhibit fractal patterns characterized by consistent temporal correlations across wide-ranging time scales. However, these patterns are disrupted by aging and psychiatric conditions. This study aims to investigate how fractal patterns vary across the sleep-wake cycle, differ based on individuals' recency of depression diagnosis, and change before and after a depressive episode.
Using actigraphy from two cohorts ( = 378), we examined fractal motor activity patterns both between individuals without depression and with varying recencies of depression and within individuals before and after depressive symptom recurrence. To evaluate fractal patterns, we quantified temporal correlations in motor activity fluctuations across different time scales using a scaling exponent, . Linear mixed models were utilized to assess the influence of the sleep-wake cycle, (recency of) depression, and their interaction on .
Fractal activity patterns in all individuals varied across the sleep-wake cycle, showing stronger temporal correlations during wakefulness (larger = 1.035 ± 0.003) and more random activity fluctuations during sleep (smaller = 0.784 ± 0.004, < 0.001). This sleep-wake difference was reduced in recently depressed individuals (1-6 months), leading to larger during sleep (0.836 ± 0.017), compared to currently depressed (0.781 ± 0.018, = 0.006), remitted (0.776 ± 0.014, < 0.001), and never-depressed individuals (0.773 ± 0.016, < 0.001). Moreover, remitted individuals who experienced depressive symptom recurrence during antidepressant tapering exhibited a larger during sleep after the symptom onset as compared to before (after: = 0.703 ± 0.022; before: = 0.680 ± 0.022; < 0.001).
These findings suggest a link between fractal motor activity patterns during sleep and depressive symptom recurrence in remitted individuals and those with recent depression.
健康成年人的运动活动波动呈现分形模式，其特征是在广泛的时间尺度上具有一致的时间相关性。然而，这些模式会因衰老和精神疾病而受到干扰。本研究旨在调查分形模式在睡眠-觉醒周期中的变化情况，基于个体最近的抑郁症诊断情况有何不同，以及在抑郁发作前后如何变化。
使用来自两个队列（n = 378）的活动记录仪，我们研究了无抑郁症个体与不同近期抑郁症个体之间以及抑郁症状复发前后个体内部的分形运动活动模式。为了评估分形模式，我们使用标度指数α量化了不同时间尺度上运动活动波动的时间相关性。采用线性混合模型评估睡眠-觉醒周期、（近期）抑郁症及其相互作用对α的影响。
所有个体的分形活动模式在睡眠-觉醒周期中均有变化，清醒时显示出更强的时间相关性（较大的α = 1.035±0.003），睡眠时运动活动波动更随机（较小的α = 0.784±0.004，P < 0.001）。与目前抑郁（0.781±0.018，P = 0.006）、缓解（0.776±0.014，P < 0.001）和从未抑郁个体（0.773±0.016，P < 0.001）相比，近期抑郁个体（1 - 6个月）的这种睡眠-觉醒差异减小，导致睡眠时α值更大（0.836±0.017）。此外，在减停抗抑郁药期间经历抑郁症状复发的缓解个体，症状发作后睡眠时的α值比发作前更大（发作后：α = 0.703±0.022；发作前：α = 0.680±0.022；P < 0.001）。
这些发现表明，缓解个体和近期患抑郁症个体睡眠期间的分形运动活动模式与抑郁症状复发之间存在联系。
