阈下抑郁者视知觉功能特点及认知神经机制

Depressive disorder, mainly showing low mood, is one of the most severe mental disorders at home and abroad. Subthreshold depression (SD) has generally been used to refer to the individuals who may have relevant depressive symptoms without meeting the diagnostic criteria of a major depressive disorder (MDD). Subthreshold depression is very popular and a mental sub-health state effecting individual quality of life. If individuals with subthreshold depression fall short of psychological intervention treatment, depressive symptoms may become more serious and develop into major depressive disorder. The present clinical diagnosis, not only SD and MDD, mainly depend on the subjective reports from psychiatrists or depressive rating scales. However, objective diagnostic methods are absent. Recent studies have showed that depression is generally associated with abnormal visual perception processing. For example, depressed patients have significantly lower visual contrast sensitivity compared to controls. Based on the previous studies about depression and visual perception processing, the current study will investigate the function characteristics and cognitive neural mechanisms of subthreshold depression from low-level to high-level visual processing stage. Then we would develop simple but effective multiple task sets using psychophysical methods. These tasks would provide new objective biomarkers for diagnosing subthreshold depression. The project will also lay the foundation to develop an objective method for diagnosing major depression disorder in the future.

抑郁障碍是以情绪低落为主的最严重的心理疾病之一，在国内外内相当普遍。阈下抑郁是指介于重性抑郁症患者和正常人之间的一种精神状态，它具有临床相关的部分抑郁症状，但又没有完全满足重性抑郁症患者的诊断标准。阈下抑郁是一种常见的心理亚健康状态，严重影响生活质量，如未得到及时的干预治疗，其抑郁症状很有可能加重，进而发展成为重性抑郁症。不管是阈下抑郁还是重性抑郁症，目前的临床诊断主要依赖于主观报告的方法，如精神科医生的症状检查和量表评估，尚缺乏有效的客观测量方法。最近的研究表明，阈下抑郁者和抑郁症患者常常伴随着异常的视知觉加工。本项目拟以已有抑郁与视知觉相关研究为基础，拟从低水平和高水平视觉加工出发，结合追踪研究的方法，多角度考察阈下抑郁者视知觉加工的特点和神经机制，进而设计出一套简易有效的视知觉行为任务测试工具集，为阈下抑郁者的早期识别和干预提供新的客观指标，也为发展诊断重性抑郁症的客观方法奠定基础。

在全世界范围内，抑郁是最普遍的心理障碍之一。阈下抑郁是指具有部分的抑郁症状但又不满足重性抑郁症诊断标准的一种心理亚健康状态，它比重性抑郁更为普遍。许多心理疾病常常伴随着视知觉功能的损害，然而阈下抑郁个体的视知觉功能是否受损目前并不清楚。考察阈下抑郁个体与健康对照个体在视知觉功能方面的差异可以为开发更为客观的抑郁临床诊断工具提供科学依据。本项目以在校大学生群体为样本，通过“两阶段筛选法”筛选符合要求的被试，并结合追踪研究设计，从低水平视知觉加工到高水平视知觉加工出发，系统地比较了阈下抑郁组个体和健康对照组个体在对比度敏感性（包括对比度差别阈限敏感性和对比度绝对阈限敏感性）、运动知觉敏感性（包括运动辨别敏感性和运动一致性敏感性）、情绪面孔知觉敏感性、动态面孔情绪识别、双眼竞争、无意识情绪面孔加工、视觉诱发电位以及长时程突触可塑性上是否存在显著差异。研究结果发现，阈下抑郁组个体较健康对照组个体对悲伤情绪表情具有更低的知觉阈限，更弱的对比度区分敏感性，更强的情绪面孔主导优势，更强的动态愤怒表情识别敏感性，以及异常的长时程突触可塑性，但是二者在运动知觉敏感性和无意识情绪面孔加工方面并没有显著的差异。这些研究结果表明，阈下抑郁个体在某些视知觉功能上受损，视知觉任务可以为阈下抑郁的早期识别和干预提供新的客观指标。