失眠是一种非常普遍的疾病，并且24小时过度觉醒的状态被认为是这种情况的关键因素。已经研究了各种过度觉醒的生理标记，包括HPA轴的活性。然而,这些研究产生了异质性的结果。这项研究的目的是定性和定量评估皮质醇水平是否存在差异，HPA轴的荷尔蒙最终产物，失眠患者和睡眠控制良好（GSC）之间。数据库PubMed,Cinahl,PsycInfo,搜索了Psycarticles和WebofScience，以比较失眠和GSC患者的皮质醇水平。20项研究（449名失眠患者，仅限于不服用任何药物的18-70岁；357GSC）符合纳入标准。对于每一项研究，计算标准化平均差异(SMD)作为效应大小的量度.结果表明，失眠患者的皮质醇水平中度升高（SMD=0.50，95％CI：[0.21-0.80]）。通过在分析中仅包括使用血液样本的研究,发现了更高的效应大小(SMD=0.67,95%CI:[0.15-1.18])。此外，一个积极的,但是失眠患者的客观睡眠损失程度与皮质醇水平的组间差异之间的相关性不大。
Insomnia is a highly prevalent disorder and a state of 24 h hyperarousal is considered as a key factor of this condition. Various physiological markers of hyperarousal have been investigated, including the activity of the HPA axis. However, these studies yielded heterogenous results. The aim of this study was to qualitatively and quantitatively evaluate whether there are differences in cortisol levels, the hormonal end product of the HPA axis, between patients with insomnia and good sleeper controls (GSC). The databases PubMed, Cinahl, PsycInfo, PsycArticles and Web of Science were searched for
case-control studies comparing cortisol levels in patients with insomnia and GSC. Twenty studies (449 patients with insomnia, limited to ages 18-70 not taking any medications; 357 GSC) met the inclusion criteria. For each study, standardized mean differences (SMD) were calculated as a measure of effect size. Results suggest that patients with insomnia show moderately increased cortisol levels (SMD = 0.50, 95% CI: [0.21-0.80]). Higher effect sizes were found by including only studies using blood samples in the analysis (SMD = 0.67, 95% CI: [0.15-1.18]). Furthermore, a positive, but insignificant association was found between the extent of objective sleep loss in insomnia patients and group differences in cortisol levels.
