Liverant Gabrielle I, Arditte Hall Kimberly A, Wieman Sarah T, Pineles Suzanne L, Pizzagalli Diego A
Department of Psychology, Suffolk University, Boston, MA, USA.
Department of Psychology and Philosophy, Framingham State University, Framingham, MA, USA.
Psychol Med. 2021 Feb 26:1-10. doi: 10.1017/S003329172100026X.
Depression and insomnia commonly co-occur. Yet, little is known about the mechanisms through which insomnia influences depression. Recent research and theory highlight reward system dysfunction as a potential mediator of the relationship between insomnia and depression. This study is the first to examine the impact of insomnia on reward learning, a key component of reward system functioning, in clinical depression.
The sample consisted of 72 veterans with unipolar depression who endorsed sleep disturbance symptoms. Participants completed the Structured Clinical Interview for DSM-IV, self-report measures of insomnia, depression, and reward processing, and a previously validated signal detection task (Pizzagalli et al., 2005, Biological Psychiatry, 57(4), 319-327). Trial-by-trial response bias (RB) estimates calculated for each of the 200 task trials were examined using linear mixed-model analyses to investigate change in reward learning.
Findings demonstrated diminished rate and magnitude of reward learning in the Insomnia group relative to the Hypersomnia/Mixed Symptom group across the task. Within the Insomnia group, participants with more severe insomnia evidenced the lowest rates of reward learning, with increased RB across the task with decreasing insomnia severity.
Among individuals with depression, insomnia is associated with decreased ability to learn associations between neutral stimuli and rewarding outcomes and/or modify behavior in response to differential receipt of reward. This attenuated reward learning may contribute to clinically meaningful decreases in motivation and increased withdrawal in this comorbid group. Results extend existing theory by highlighting impairments in reward learning specifically as a potential mediator of the association between insomnia and depression.
抑郁症和失眠症常常同时出现。然而，关于失眠影响抑郁症的机制却知之甚少。近期的研究和理论强调奖励系统功能障碍是失眠与抑郁症之间关系的潜在中介因素。本研究首次在临床抑郁症患者中考察失眠对奖励学习的影响，奖励学习是奖励系统功能的关键组成部分。
样本包括72名患有单相抑郁症且认可存在睡眠障碍症状的退伍军人。参与者完成了《精神疾病诊断与统计手册》第四版的结构化临床访谈、失眠、抑郁和奖励处理的自我报告测量，以及一项先前验证过的信号检测任务（皮扎加利等人，2005年，《生物精神病学》，第57卷第4期，第319 - 327页）。使用线性混合模型分析检查为200个任务试验中的每一个计算的逐次试验反应偏差（RB）估计值，以研究奖励学习的变化。
研究结果表明，在整个任务过程中，失眠组相对于嗜睡/混合症状组的奖励学习速率和幅度有所降低。在失眠组中，失眠症状更严重的参与者奖励学习速率最低，随着失眠严重程度降低，整个任务过程中的反应偏差增加。
在抑郁症患者中，失眠与学习中性刺激和奖励结果之间关联的能力下降以及/或者根据奖励的不同接收情况改变行为的能力下降有关。这种减弱的奖励学习可能导致该共病群体在临床上有意义的动机降低和退缩增加。研究结果通过特别强调奖励学习受损是失眠与抑郁症之间关联的潜在中介因素，扩展了现有理论。
