The traumatic stress response in child maltreatment and resultant neuropsychological effects

Abstract

Child maltreatment is a pervasive problem in our society that has long-term detrimental consequences to the development of the affected child such as future brain growth and functioning. In this paper, we surveyed empirical evidence on the neuropsychological effects of child maltreatment, with a special emphasis on emotional, behavioral, and cognitive process–response difficulties experienced by maltreated children. The alteration of the biochemical stress response system in the brain that changes an individual's ability to respond efficiently and efficaciously to future stressors is conceptualized as the traumatic stress response. Vulnerable brain regions include the hypothalamic–pituitary–adrenal axis, the amygdala, the hippocampus, and prefrontal cortex and are linked to children's compromised ability to process both emotionally-laden and neutral stimuli in the future. It is suggested that information must be garnered from varied literatures to conceptualize a research framework for the traumatic stress response in maltreated children. This research framework suggests an altered developmental trajectory of information processing and emotional dysregulation, though much debate still exists surrounding the correlational nature of empirical studies, the potential of resiliency following childhood trauma, and the extent to which early interventions may facilitate recovery.

Introduction

Child maltreatment is recognized as a widespread and pervasive problem in the United States. The U.S. Department of Health and Human Services (2007) reported 896,000 cases of substantiated maltreatment in 2005 alone. Clinicians, researchers and the general public share a common concern regarding the child victims of maltreatment. There is a dearth of literature on child maltreatment that supports the salience of preventative measures, effective interventions, and access to services for recovery from maltreatment. Despite the breadth and depth of information regarding child maltreatment, researchers are still exploring the vicissitudes of maltreatment in our society.

Child maltreatment occurs in several different forms. U.S. Department of Health and Human Services, Administration on Children, Youth and Families (2007) defines the different forms of child maltreatment within a commission–omission paradigm. Physical and sexual abuse are acts of commission of excessive physical punishment and inappropriate sexual contact with a child, respectively, whereas neglect is an act of omission, with harmful effects resulting from the lack of a caregiver's actions for a child's welfare (DHHS, 2007). Exposure to domestic violence diverges from the commission–omission definitional schema for child maltreatment in that the action is directed to someone other than the child, but is nonetheless resultantly harmful to the child's welfare (Fantuzzo & Mohr, 1999). Furthermore, it is also common for children to experience multiple forms of maltreatment (Carter et al., 1999, Hulme and Agrawal, 2004). In community studies, other researchers note a significant percentage of their samples to have experienced multiple forms of abuse (Bifulco et al., 2002, Silverman et al., 1996). Several researchers highlight the need for more explicit descriptions of maltreatment in research studies (e.g., Manly, 2005). With such a variety of definitional schema in the literature, many researchers are calling for and developing classification systems for child maltreatment (e.g., Cicchetti, 2007). For these reasons, it is important to approach maltreatment from the unifying definition of an experience outside the average expectable environment that has the potential to harm a child.

Maltreatment has a variety of effects. Some children experience short-term problems immediately following their maltreatment, while others go on to have pervasive problems for months or even years (e.g., Kendall-Tackett, Williams, & Finkelhor, 1993). Fortunately, there is also a percentage of resilient children that do not exhibit observable maladaptive effects to maltreatment (e.g., Cicchetti, 2007). Children that do experience difficulties after enduring maltreatment may display one or several different types of problems. These types of problems can range from externalizing problems (i.e., conduct problems, aggression, and risky sexual behavior), to internalizing problems (i.e., depression, self-harm, and suicidality). Similarly, researchers estimate that 20–63% of maltreated children have an extremely aversive response and develop Posttraumatic Stress Disorder (Gabbay, Oatis, Silva, & Hisrch, 2004). While these behaviors may result from many different experiences, when the behavior is clearly preceded by child maltreatment it can be inferred that the stress of the maltreatment experience was causally involved in the behavioral response.

There has been increasing attention to the traumatic stress response. Major contributions have been made in recent years to the child maltreatment literature base by psychiatrists, clinical psychologists, and neuropsychologists utilizing this framework. The strength of this approach is that it allows different fields to synthesize findings from different populations and methodologies under a common philosophy to work towards understanding the common problem of child maltreatment. Further, a unifying philosophy can orient research in the field without impingement of DSM criteria on methodological design. With such a breadth of research contributions, there is also great depth added to the field. Clinical psychology has provided much thus far in terms of research on the individual psychological effects of child maltreatment (e.g., Cicchetti & Toth, 2005). Similarly, much has been offered on the biochemical, brain structural, and physiological effects of maltreatment through neuroimaging work (e.g., Bremner et al., 2003, De Bellis, 2005, Teicher, 2002). Neuropsychology has afforded the opportunity to enhance our understanding of the brain–behavior relationship by systematically testing individuals' functional capacities that are hypothesized to be affected from the neuroimaging literature (e.g., Liberzon and Martis, 2006, Shin et al., 2006). And finally, animal studies allow for more experimental rigor and more direct examination of the casual effects of maltreatment than clinical studies (e.g., Cohen and Zohar, 2004, Harvey et al., 2006).

Cicchetti and Lynch (1993) offer one of the most widely accepted frameworks for understanding the intricacies of child maltreatment. Their ecological–translational model accounts for the dynamic child–environment relationship within a developmental framework. Child maltreatment is viewed as an adversity outside the realm of the average expectable environment. When a child is maltreated, her or his developmental trajectory is altered. This altered trajectory has innumerable costs (Cicchetti, 2007). These costs range from the immediate individual effects, such as medical bills and the cost of therapeutic services for victims and perpetrators, to the long term effects such as court costs of legal proceedings. Also important are the less tangible and more pervasive effects such as pain, suffering, and diminished quality of life for victims.

The purpose of this literature review is to elucidate how the traumatic stress response to child maltreatment affects neuropsychological functioning following psychological trauma. In order to understand the traumatic stress response on these functional abilities, it is important to review contributing areas. As it is understood that there is a systematic biochemical response to stress in the brain, psychologists need to understand the neurochemical cascade that results from a traumatic stress response (e.g., De Bellis, Hooper, & Sapia, 2005). Thus, the neurochemical effects of the traumatic stress response are first explained from adult clinical and animal studies. Second, it is important to gain a broad understanding of general brain development in children so as to have an appreciation for what an altered developmental trajectory could affect (Glaser, 2000). Third, specific studies of the traumatic stress response to child maltreatment will be examined in the clinical literature (e.g., Cohen, Perel, De Bellis, Friedman, & Putnam, 2002). Fourth, the biological response systems that were hypothesized to be altered by the traumatic stress response and linked to behavioral symptom response in maltreated children will be explored in terms of any manifested neuropsychological differences in functioning (e.g., Liberzon & Martis, 2006). Finally, we point out several less explored areas that deserve future research attention and suggest approaches to address important issues in those areas, including inclusive criteria for subject recruitment, robust assessment of children's functioning, and replication of adult neuropsychological studies with children and adolescents.