Factores epigenéticos y psicológicos asociados a la negligencia materna

Resumen

The category of "child abuse" is extensive and encompasses various types of abuse. However, this Thesis focuses solely on child abuse that occurs through neglectful caregiving. This type of abuse is considered the most frequent and the one with the most severe consequences for child development (Bernat y Villar, 2019). Child neglect has been approached from different perspectives, and one of the things that stands out the most is its difficulty in being detected or categorized successfully, which means that in many situations, these cases are not detected and go unnoticed. There are many definitions of child neglect, but in this Thesis, the classification provided by the Child Protection Services has been taken as a reference, based on the classic contributions of Barnett et al. (1993). According to these considerations, child neglect is defined as the absence of satisfaction of the most basic needs of children, both physical, cognitive, and emotional, and, in addition, the imminent risk to which these minors may be subject due to the lack of supervision. The definition of neglect refers to both parents; however, in this Thesis we will focus on the maternal figure, following the different reports that indicate that it is more prevalent in the female gender (Centro Reina Sofía, 2011). However, it is necessary to point out that these statistics should be taken with caution since, in most cases, children are under the supervision and care of the mother and not so much the father. According to the literature, among the severe consequences that this type of abuse is associated with are alterations in cognitive development, in the establishment of an adequate bond of attachment, in the development of social skills, and a greater predisposition to suffer some psychopathology, and even, to follow the same pattern of caregiving with their children (Neumann, 2017; Talmon et al., 2019; Velarde Arcos y Ramírez Flores, 2017). Functional and structural alterations at the brain level have also been observed, mainly in regions such as the hippocampus, the amygdala, the prefrontal cortex, and the corpus callosum (Lu et al., 2019; Monteleone et al., 2019; Van Rooij et al., 2020). In addition to all these consequences and alterations, there is increasing evidence showing that traumatic and abusive experiences cause alterations at a more molecular level through different epigenetic mechanisms such as DNA methylation. Such a process affects gene expression, leading to the appearance of various diseases and less adaptive behaviors. The majority of the studies on social epigenetics have focused on the alterations that the closest environment causes on the methylation of three specific genes, such as NR3C1 ( Ramo-Fernández et al., 2019), FKBP5 (Tozzi et al., 2018), and SCL6A4 (Peng et al., 2018). Despite the enormous interest in this topic, few works have been dedicated to studying the psychological or epigenetic factors associated with negligent behavior. That is why one of the objectives of this dissertation is to investigate this topic and achieve greater knowledge about other dimensions related to the maternal neglect profile to provide the Child Protection Services with more effective tools for their detection and intervention. Four are the general objectives set out in this Thesis. The first objective (addressed in the first study) sought to identify a particular set of variables stemming from the mother's closest and immediate environment and from the mother-child relationship that was sufficiently diagnostic to allow a greater preventive identification of these negligent behaviors. The second general objective (addressed in the second study) aimed to determine whether there were certain biases in mothers when evaluating children's emotional expressions (negativity and approximation) and the role that alexithymia, usually high in these mothers, could be playing. The third objective (addressed in the third study) examined the extent to which there were differences in epigenetic aging between mothers exhibiting negligent behaviors and non-negligent control mothers. The fourth (in the third study too) examined whether empathy could exert a protective role on epigenetic aging in the group of mothers with negligent behaviors. The participants of these studies were two groups of mothers (mothers with negligent behaviors (NG) and control mothers (CG)) and their children. Although the sample was the same in all the studies, the number of participants varied, as reflected in Chapter 3. All the mothers signed the differently informed consents both for their participation and their children’s participation. Regarding the instruments, different questionnaires were used to measure sociodemographic variables, personality variables (Alexithymia, Adult Attachment, Social Anhedonia, and Empathy), psychopathological variables, traumatic experiences, and previous abuse history. A scale to examine the emotional accessibility shown in situations of playful mother-child interaction was also used. For DNA methylation analysis, two specific tools for collecting saliva (Real's saliva collection kit) and DNA extraction (Maswell's DNA extraction kit) were used. All the analyses were carried out using the R statistical program (R Core Team 2020). Concerning the results of the first study aimed to find out the set of variables with high diagnostic power, it is relevant to highlight a high diagnostic accuracy (80-82% of NG and 92% of CG) in the child classification as neglected or not, for a set of select variables. Those factors that multiply the risk of the children being victims of neglect are: having a physically neglected and depressed mother, living in families that receive institutional financial assistance and in large families. As protective variables, having an older mother and showing greater mother-child dyadic emotional availability were the most critical factors. Identifying this select group of characteristics of the immediate care environment with high classifying power favors the ability to make an early diagnosis, and that preventive intervention is more feasible and effective for the Child Protection Services. Regarding the second study, an experimental study aimed at examining the mother’s differential appraisals of children faces, the results indicate that both groups of mothers evaluate children's faces as more pleasant and with a greater response to approximation than adult faces. However, two types of biases were found: first, a less pleasant assessment of neutral faces, like crying, in the high levels of alexithymia characteristic of mothers with negligent behaviors; and, secondly, a greater approximation response to crying appeared in mothers with negligent behaviors. This tendency could not be explained by their high levels of alexithymia since these generate a lower approximation response. These results are essential to consider in family reunification processes, which generally fail in these cases. Once known these biases, their correction should be considered a therapeutic objective that allows improving maternal capacities and favoring the preservation or successful family reunification. Finally, the results of the third study showed an increase in epigenetic age acceleration in mothers with negligent behaviors compared to control mothers even after adjusting for chronological age, number of children, perception of financial aid, stressful life events, the previous history of abuse, and psychopathological variables. The group interaction effects showed how the epigenetic acceleration decreased in the negligent group with having greater empathic concern, highlighting the protective role of affective empathy. However, having a low educational level and living in a biparental family showed the opposite effect, acting as risk factors increasing the epigenetic acceleration for mothers with negligent behaviors. These findings open the searching for new protective factors associated with the caregiver's behavior acting that may reduce epigenetic aging, allowing for more focused intervention. In general, all the results derived from this Thesis are expected to help better categorize child neglect, make better and more accurate diagnoses, and intervene most effectively.