青少年皮质醇觉醒反应与负性情绪的关系及机制

Adolescence is an important period to study psycho-physiological responses to stress. Adolescents experience rapid hormonal changes and social challenges which bring a surge of emotion. The CAR is the morning spike in circulating cortisol after awakening as a preparation for the upcoming demands of the day. The CAR has a relatively high intra-individual stability which was used as a reliable trait biomarker of the neuroendocrine activity. It has been found that the CAR is closely related to cognition, health, brain structure and behavior. There is growing evidence of a decreased CAR in individuals may indicate an over consumption of neuroendocrine resources as a consequence of chronic stress. We also found that the CAR was predictive of the function of response inhibition on the same day. The present study aims to investigate the relationship between individual differences in the CAR as a trait in adolescents and emotion as well as the underlying neural mechanisms using behavioral, ERP and physiological methods. The negative emotion is going to be examined with attention bias, regulation and daily responses. The results of the present study will provide further knowledge of adolescents' emotion development, mechanism and empirical evidences for the prediction and prevention of emotional problems.

青少年时期是研究心理-生理应激反应的一个重要时期，急剧的激素水平变化和社会化挑战带来强烈的情绪变化。皮质醇觉醒反应（CAR）指皮质醇水平在晨醒后短暂升高达到峰值，反映了对即将到来的心理负荷的预期和神经内分泌资源的准备，具有较高的个体内稳定性，常被看成神经内分泌反应的特质。已有研究发现CAR与认知、健康、脑结构和行为密切相关，较低的CAR也许意味着神经内分泌资源由于个体长期的慢性应激状态而过度的消耗。前期我们的研究也发现，CAR能够正向预测当天下午的反应抑制能力。本项目以负性情绪偏向、调节和日常情绪反应为切入点，试图通过行为、脑电和生理测量等方法探讨青少年作为特质的CAR与负性情绪的关系及背后的机制。本项目的研究结果有助于阐释青少年情绪问题的发展及机制，为青少年不良情绪问题的发生和发展进行有效的预测和早期干预提供科学依据。

在社会转型不断加快、社会结构深刻变动的当下，青少年在日常环境中面临诸多社会和情感压力源，研究表明青少年HPA轴的功能异常和负性情绪相关。皮质醇是肾上腺皮质产生的一种激素，它在应对压力中扮演重要角色，又被称为“压力荷尔蒙”。正常人的肾上腺皮质分泌皮质醇有典型的昼夜节律，清晨唾液皮质醇觉醒反应(cortisol awaking response, CAR)是觉醒后头一个小时体内皮质醇浓度的变化, 是反映下丘脑—脑垂体—肾上腺皮质(Hypothalamic-pituitary-adrenal cortex, HPA)轴功能的稳定指标, 反映了对未来一天心理负荷的预期，与日常慢性应激水平密切相关。从情绪认知的时间轴角度，本研究分别关注青少年CAR与负性情绪的注意、调节和反应之间的关系。结果发现中等程度的CAR与最佳的错误监控能力相联系。青少年CAR与对负性情绪图片的注意偏向显著负相关，CAR越大，LPP差异波平均波幅越小，表明对负性图片的有意注意越弱。CAR能够预测应激-负性情绪的斜率，CAR越大的个体，日常生活应激事件导致的负性情绪越强；反之，CAR越小，生活应激对日常情绪的影响越小。除了客观可控性外，主观上的控制也是调节HPA轴激活的心理因素。日周期类型与CAR之间存在显著负相关。.本项目研究结果一方面丰富了皮质醇觉醒反应的预期假设理论，另一方面为青少年相关情绪问题的预防和干预提供了实证证据。