Department of Psychology, Faculty of Humanities and Social Sciences, University of Bath, Bath, UK; Population Health Sciences, Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, UK.
Department of Psychology, Faculty of Humanities and Social Sciences, University of Bath, Bath, UK; Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa.
Psychoneuroendocrinology. 2020 Nov;121:104846. doi: 10.1016/j.psyneuen.2020.104846. Epub 2020 Aug 22.
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is implicated in the pathophysiology of post-traumatic stress disorder (PTSD). However, there has been little study of HPA stress reactivity in association with PTSD symptoms (PTSS) in children; and there is limited research on PTSD in low and middle-income countries, where trauma exposure is more common and co-occurring stressors more likely.
We assessed the relationship between PTSS and cortisol stress reactivity in children aged 13 years (N = 291) from an impoverished South African community. HPA axis stress reactivity was indexed by salivary cortisol during the Trier Social Stress Test (TSST).
In regression analyses both trauma exposure and PTSS showed small inverse associations with total cortisol output (area under the curve with respect to ground) during the TSST, but PTSS effects did not withstand correction for covariates. In addition, hierarchical linear modelling (HLM) found that PTSS were associated with alterations in the shape of the profile of cortisol reactivity that were moderated by sex. In girls, PTSS were associated with reduced linear slope but larger quadratic slopes, whereas the opposite pattern was found in boys. Thus, elevated PTSS were associated with overall blunted profiles of cortisol stress reactivity in girls, but a larger quadratic slope in boys reflects a steeper cortisol increase and decline in boys. There was no relationship between trauma exposure (with or without PTSS) and cortisol reactivity profiles in HLM analyses.
In children from a high adversity, low and middle income country context, sex specific associations were found between PTSS and cortisol responses to psychosocial stress. Further research should probe HPA axis functioning more comprehensively in such populations to understand the biological associations of PTSS.
下丘脑-垂体-肾上腺（HPA）轴的失调与创伤后应激障碍（PTSD）的病理生理学有关。然而，对于儿童 PTSD 症状（PTSS）与 HPA 应激反应之间的关系研究甚少；而且在中低收入国家，创伤暴露更为常见，同时存在更多的共发压力源，关于 PTSD 的研究也很有限。
我们评估了南非贫困社区 13 岁儿童（N=291）的 PTSD 症状与皮质醇应激反应之间的关系。通过 Trier 社会应激测试（TSST）评估 HPA 轴应激反应，以唾液皮质醇为指标。
在回归分析中，创伤暴露和 PTSD 症状都与 TSST 期间总皮质醇输出（相对于基础的曲线下面积）呈小的负相关，但 PTSD 症状的影响在经过协变量校正后并不显著。此外，分层线性模型（HLM）发现，PTSD 与皮质醇反应形态的改变有关，而这种改变受性别调节。在女孩中，PTSD 与线性斜率减小但二次斜率增大有关，而男孩则出现相反的模式。因此，在女孩中，较高的 PTSD 症状与皮质醇应激反应的整体迟钝模式有关，而男孩中更大的二次斜率则反映了皮质醇的急剧增加和下降。在 HLM 分析中，创伤暴露（无论是否伴有 PTSD 症状）与皮质醇反应模式之间没有关系。
在高逆境、中低收入国家背景下的儿童中，发现 PTSD 症状与心理社会应激下皮质醇反应之间存在性别特异性关联。进一步的研究应该更全面地探究 HPA 轴功能，以了解 PTSD 的生物学关联。
