虐待和忽视是指会对儿童的健康、发展或自尊造成实际或潜在伤害的各种形式的虐待和忽视。以往大量实证研究揭示了虐待和忽视对儿童发展具有广泛而深远的负面影响，近年来也有研究者开始探索虐待和忽视与儿童生理应激系统（如，下丘脑-垂体-肾上腺轴；hypothalamic-pituitary-adrenal axis, HPA axis）的关联。

然而，以往关于虐待和忽视与儿童HPA轴功能的实证研究尚未得到统一结论。逆境的维度取向作为逆境领域最新的研究取向，指出探索不同维度的逆境（如，虐待属于威胁类逆境，忽视属于剥夺类逆境）与个体神经生理系统可能的特异性关联，可以更精细、全面地理解逆境与个体神经生理层面的关系，这可能有助于厘清或解释这一领域研究结果存在分歧的原因。同时，尽管研究者指出HPA轴功能可能在儿童期到青少年期的过渡期间出现重要转变，但以往少有实证研究采用追踪设计考察儿童HPA轴功能随年龄增长出现的个体内变化，更少有研究在此基础上探讨虐待和忽视与HPA轴功能这一变化的关系。最后，目前亦鲜有研究探索虐待和忽视与儿童HPA轴功能关系间的个体差异，例如个体积极资源能否调节虐待和忽视与HPA轴功能的关系、上述关系在女生和男生中是否呈现出相同的模式。基于此，本研究以日常皮质醇节律的多个指标（觉醒皮质醇水平、皮质醇觉醒反应、日间皮质醇斜率）作为HPA轴日常基础活动性的反映，探讨虐待、忽视与儿童基线时的日常皮质醇节律及其在一年间发展变化可能的特异性关联，考察心理弹性在上述关系间的调节作用，并在女生和男生中分别对上述研究问题进行检验。

本论文以安徽省两所学校的四、五年级的儿童为被试。在基线测查时，进行了问卷调查，并连续三天、每天三次收集了儿童的日常唾液皮质醇样本；在大约一年之后的第二次测查中，再次连续三天、每天三次收集了儿童的日常唾液皮质醇样本。研究一利用基线时儿童自我报告的问卷数据及客观的日常皮质醇数据（N = 304；9~13岁，平均年龄为10.80±0.84岁），采用多水平模型，考察了虐待、忽视与多个日常皮质醇指标的特异性关联，以及心理弹性在上述关系间的调节作用，并在女生(n = 100)和男生(n = 204)中分别进行了上述检验。研究二利用基线时儿童自我报告的问卷数据以及两次测查时的日常皮质醇数据，且参考以往对日常皮质醇追踪数据进行分析的研究，将参与了任一次日常皮质醇测量的被试纳入分析中(N = 312)，采用多水平模型，考察了基线时的虐待、忽视与各日常皮质醇指标在一年间变化的特异性关联，以及基线时的心理弹性在上述关系间的调节作用，并在女生(n = 103)和男生(n = 209)中分别进行了上述检验。

本研究发现，仅在女生中，虐待、忽视可能与日常皮质醇节律存在一定的特异性关联，具体有以下三种形式：（1）关联指标的特异性，即，仅有虐待会与女生的日间皮质醇斜率相关联，仅有忽视会与女生（基线时更低）的皮质醇觉醒反应相关联；（2）关系方向的特异性，即，虐待与女生基线时更低的觉醒皮质醇水平相关联（仅在心理弹性高的女生中成立），而忽视与女生基线时更高的觉醒皮质醇水平相关联；（3）关系时程的特异性，即，仅有虐待（而非忽视）会与女生日常皮质醇指标在一年间的变化（觉醒皮质醇水平更少地降低、日间皮质醇斜率更大程度地变陡峭）相关联。

本研究亦发现了心理弹性在虐待与女生日常皮质醇节律关系间的调节作用：（1）心理弹性调节了虐待与女生基线时觉醒皮质醇水平的关系，即，虐待与女生基线时更低的觉醒皮质醇水平的关系仅在高心理弹性的女生中成立；（2）心理弹性调节了虐待与女生日间皮质醇斜率在一年间变化的关系，即，虐待与日间皮质醇斜率更大程度地变陡峭的关系仅在低心理弹性的女生中成立。心理弹性在虐待与男生日常皮质醇节律的关系间、忽视与女生和男生日常皮质醇节律的关系间均没有显著的调节作用。

本研究以逆境的维度取向作为最主要的理论指导，通过采用横断和追踪相结合的设计、主观自我报告与客观生理指标采集相结合的方法，精细探讨了虐待、忽视与儿童日常皮质醇节律的特异性关系，同时关注了儿童皮质醇节律随年龄增长出现的个体内变化，并探讨了上述关系中的个体间差异（心理弹性、性别）。研究结果可能初步揭示了虐待、忽视与儿童日常皮质醇节律产生特异性关联的表现方面和具体形式，为逆境的维度取向提供了来自生理应激领域且基于中国儿童的支持与补充。本研究关于虐待和忽视与儿童日常皮质醇节律的个体间差异的结果，也可以深化和细化对于逆境与儿童HPA轴功能关系的理解，可能揭示了这一关系间的“易感”与“弹性”人群，对虐待和忽视的预防与干预工作有一定启示。总结来看，本研究结果丰富了虐待和忽视与儿童生理应激系统领域的实证研究，在一定程度上对该领域的理论进行了补充和细化，并可以为虐待和忽视的精准预防和干预提供科学依据。

Child maltreatment is the abuse and neglect that results in actual or potential harm to the child’s health and development. There has been abundant evidence that speaks to the pervasive and pernicious effects of maltreatment on child development in both the short and long term. A substantial body of research has indicated that child maltreatment may drive anomalies in the hypothalamic—pituitary—adrenal (HPA) axis functioning in recent years.

However, mixed findings emerged among studies concerning the relations between maltreatment and child HPA axis functioning. As the cutting edge framework in the research field of stress and adversity, the dimensional approach suggests that, elucidating the distinct effects of specific dimensions of adversity (e.g., abuse is viewed as threat while neglect is viewed as deprivation) on individuals’ neurophysiological systems may contribute to a more nuanced and comprehensive understanding about the associations between adversity and neurophysiology. Therefore, the dimensional approach may facilitate the explanation about the inconsistency in research findings in the field of adversity and neurophysiology. Although it has been proposed that there may be salient developmental changes in HPA axis functioning during the transition from childhood into adolescence, limited studies investigate the profound changes in HPA functioning within individuals using a longitudinal design, and less is known about how abuse and neglect may be associated with these changes in HPA axis functioning. Moreover, there is a remarkable paucity of studies of individual differences in the links form abuse and neglect to child HPA axis functioning. For instance, whether individual resources could moderate the relations between abuse and neglect and HPA axis functioning, and whether these relations differ between girls and boys. To fill these gaps, the present study used multiple parameters of diurnal cortisol rhythm (i.e., awakening cortisol, cortisol awakening response, diurnal cortisol slope) to reflect the basal HPA axis activity, and examined the potentially distinct effects of abuse and neglect on child diurnal cortisol at baseline assessment and diurnal cortisol changes in one-year period among girls and boys, respectively. Furthermore, the moderating effects of resilience in above associations were also investigated.

Participants were children recruited from two elementary schools in Anhui Province. At baseline assessment, children completed self-reported questionnaires and provided saliva cortisol samples three times per day on three consecutive days. Child’s saliva cortisol samples were collected again (three times per day on three consecutive days) about one year later. In study one, using the cross-sectional data (N  = 304; age range = 9~13, M_age  = 10.80, SD  = 0.84), multilevel analyses were conducted to test the possibly distinct effects of abuse and neglect on child diurnal cortisol parameters and the moderating effects of resilience in such associations. Analyses were also respectively performed in girls (n  = 100) and boys (n  = 204). In study two, using the self-reported data at baseline assessment and diurnal cortisol data at two time points (N  = 312; according to prior research, children who had valid cortisol data at either assessment were included), multilevel analyses were conducted to examine the potentially distinct effects of abuse and neglect at baseline on changes in child diurnal cortisol parameters during one year and the moderating effects of baseline resilience in such associations. Analyses were also respectively performed in girls (n  = 103) and boys (n  = 209).

Results showed that there may be distinct effects of abuse and neglect on child diurnal cortisol rhythm, although these effects were only observed in girls but not in boys. Specifically, the distinct effects may emerge as: (1) The distinct diurnal cortisol parameters. That is, only abuse was associated with diurnal cortisol slope, and only neglect was associated with lower cortisol awakening response at baseline. (2) The distinct directionality in associations. That is, abuse was associated with lower awakening cortisol at baseline (only for girls with high levels of resilience), whereas neglect was associated with higher awakening cortisol at baseline. (3) The distinct time scales. That is, only abuse but not neglect was associated with changes in cortisol parameters during one-year period (i.e., less decreases in awakening cortisol and more increases in steepness of diurnal cortisol slope).

The present study also found the moderating roles of baseline resilience in the links from abuse to diurnal cortisol parameters among girls: (1) Resilience at baseline moderated the association between abuse and awakening cortisol at baseline, such that the negative association between abuse and awakening cortisol at baseline was significant only for girls with high levels of resilience. (2) Resilience at baseline moderated the association between abuse and changes in diurnal cortisol slope in one-year period, such that abuse was associated with more increases in steepness of diurnal cortisol slope only for girls with low levels of resilience. Resilience did not moderate the relations between abuse and diurnal cortisol parameters in boys or the relations between neglect and diurnal cortisol parameters in girls and boys.

Building upon the dimensional approach in the research field of adversity, the present study combined the cross-sectional and longitudinal design and used both self-report data and physiological measures to explore the distinct effects of abuse and neglect on child diurnal cortisol rhythm, and investigated the within-individual changes in diurnal cortisol parameters. Furthermore, this study also revealed the individual differences (i.e., the roles of resilience and sex) in above associations. The present findings may provide preliminary evidence for how abuse and neglect may be distinctly associated with child diurnal cortisol rhythm and also indicate the detailed patterns of these relations. Hence, these results may lend support and supplement for dimensional approach from the perspective of stress physiology and among a sample of Chinese children. Moreover, the findings concerning individual differences may deepen our understanding about the relations between adversity and child HPA axis functioning, as these results may reveal the “vulnerable” and “resilient” individuals in associations between abuse and neglect and diurnal cortisol parameters. In conclusion, the present study adds to the literature on maltreatment and child stress physiology, and also provides evidence and supplement for theories in this research field. Findings in this study may also have implications on precious prevention and intervention of child maltreatment.