Department of Psychiatry, Yale University, New Haven, CT, USA.
Psychoneuroendocrinology. 2010 Oct;35(9):1363-73. doi: 10.1016/j.psyneuen.2010.03.011. Epub 2010 Apr 24.
There is widespread consensus that stress induces dramatic physiological changes, but no agreement on the quantitative parameters that are appropriate to measure these responses. More importantly, the interpretation of various stress measurements, and how individual responses should be evaluated, has not been properly addressed. Even the definition of baseline, against which stress responses must be measured, is not clearly established. The current experiment sought to address these shortcomings by comparing the predictive value of different calculated parameters for psychosocial and physiological measures of stress across individuals. Subjects were 29 male and 59 female healthy undergraduate students with saliva samples collected over a 3-h interval that included a Trier Social Stress Test. Salivary cortisol and alpha-amylase response were analyzed using the absolute concentration, the percent change in concentration, the area under the curve (Pruessner et al., 2003), and the arrival index (change from arrival to 1h after arrival). The arrival index correlated with the subsequent stress response for both cortisol (r=0.76, p<0.01) and alpha-amylase (r=0.86, p<0.01). The arrival index for both cortisol and alpha-amylase was also related to subjective ratings of anxiety following the psychosocial stressor. A subset of individuals with high self-reported anxiety also displayed higher reactivity in response to the psychosocial stressor. Thus, the magnitude of the difference in cortisol and alpha-amylase between arrival and 1h after arrival was a predictor of subsequent stress reactivity. These findings suggest that different psychosocial profiles may be reflected in cortisol and alpha-amylase changes. For this reason: (1) a recovery period after arrival is essential to establish a baseline, (2) the difference between arrival and post-recovery period baseline should be included in experimental designs as a predictive variable, and (3) transformation of individual measures into proportional changes relative to the arrival sample is very likely to obscure important underlying individual differences.
人们普遍认为压力会引起明显的生理变化，但对于哪些定量参数适合用来衡量这些反应，尚无共识。更重要的是，各种压力测量的解释以及如何评估个体反应，尚未得到妥善解决。甚至基准的定义，即必须根据其来衡量压力反应，也没有明确确立。本实验旨在通过比较不同计算参数对个体间社会心理和生理压力测量的预测价值来解决这些缺点。研究对象为 29 名男性和 59 名健康的本科女学生，在包括特里尔社会应激测试在内的 3 小时间隔内采集唾液样本。使用绝对浓度、浓度变化百分比、曲线下面积（Pruessner 等人，2003 年）和到达指数（到达时到到达后 1 小时的变化）分析唾液皮质醇和α-淀粉酶的反应。到达指数与皮质醇（r=0.76，p<0.01）和α-淀粉酶（r=0.86，p<0.01）的随后应激反应相关。皮质醇和α-淀粉酶的到达指数也与社会心理应激后焦虑的主观评分相关。一组自述焦虑较高的个体对社会心理应激也表现出较高的反应性。因此，皮质醇和α-淀粉酶在到达时和到达后 1 小时之间的差异幅度是随后应激反应性的预测因子。这些发现表明，不同的社会心理特征可能反映在皮质醇和α-淀粉酶的变化中。因此：（1）到达后的恢复期对于建立基准至关重要，（2）应将到达后恢复期和到达时之间的差异作为预测变量纳入实验设计中，（3）将个体测量值转换为相对于到达样本的比例变化很可能掩盖重要的潜在个体差异。
