Journal of Childhood & Developmental Disorders

Description

The fundamental biology of developmental trauma has been the subject of preclinical research in rodents and nonhuman primates in recent years, and clinical research has begun to clarify the effects of one-time traumatic events as well as exposure to ongoing abuse and neglect. These studies have demonstrated that, whereas chronic maltreatment or unavoidable recurring traumatization, such as exposure to repeated medical or surgical procedures, has pervasive effects on neurobiological development, isolated traumatic incidents typically produce discrete conditioned behavioral and biologic responses to reminders of the trauma. Accidents, child abuse, and neglect frequently co-occur. Children who are neglected, for instance, are more likely to sustain burns, and children whose parents abuse alcohol or drugs are more likely to suffer from physical and sexual abuse.

The DSM-IV field trial for posttraumatic stress disorder (PTSD) revealed that the age at which children are first traumatized, the frequency of their traumatic experiences, and the degree to which caregivers contribute to the event being traumatic all have a significant impact on the degree of psychological damage they sustain. Self-regulation issues, aggression against oneself and others, attention and dissociation issues, physical issues, and issues with self-concept and the capacity to negotiate satisfying interpersonal relationships are all manifestations of this.

The presence of an attachment figure who helps regulate the child's physiologic arousal by balancing stimulation and soothing is necessary for the development of normal play and exploration. Field and Reite have demonstrated that when mothers and babies interact, their heart rate curves parallel each other. As the child alternates between exploring the environment and returning to their mothers, the ability of caregivers to modulate physiologic arousal fosters the child's attachment to them and facilitates a smooth transition between activities that increase and decrease arousal. Stern refers to this as "affect attunement" between infants and their caregivers. About 48% of the mothers' behaviors in his studies were described as attunements or mirroring: echoing the infant's behavior in a different or the same modality.

The Spectrum of Psychopathology

Caregivers not only protect children from the effects of stressful situations by soothing them when it's needed, but they also play a crucial role as psychoneurobiologic regulators of the child's affective states by helping the child develop the biologic structures needed to deal with stressful situations in the future. It appears that having controllable stress responses as a baby is necessary for the formation of connections in the central nervous system that make it easier to deal with subsequent stresses.

Bowlby and Stern, two researchers who study attachment, have proposed that the attachment relationship serves as an internal world map. The child's views of themselves, their caregivers, and the way the world works are all determined by this map.By connecting the current experience to previous emotional responses, emotions assist in interpreting the meaning of the incoming stimuli. The nature and adaptability of their behavioral responses are determined by the emotional acuity of particular stimuli. An organism is likely to be able to come up with a flexible response as long as emotions are controlled by (cognitive) awareness of what is happening. Both feeling and thinking are important: Children who have no contact with their emotions and only use cognitive strategies to deal with their environment are just as disturbed as children who only use emotion.

Changes in neurotransmitter systems that control the stress response may play a role in the relationship between childhood trauma and the development of mood and anxiety disorders.18 In particular, CRF is a major mediator of the stress response in mammals and coordinates the behavioral, autonomic, endocrine, and immune responses to stress. Postmortem tissue from depressed patients has been found to contain an increased number of CRF immunoreactive neurons and CRF mRNA expression, as well as elevated CSF CRF concentrations in combat veterans with PTSD. The 41-amino acid CRF sequence was characterized by Vale and colleagues in 1981, and it was later discovered to be heterogeneously distributed throughout the CNS.

Neurocircuits Affected by Stress

A crucial component of the neuroendocrine stress-response system, corticotropin-releasing factor is found in high concentrations in the medial parvocellular region of the hypothalamic paraventricular nucleus. CRF is released into the hypothalamo-hypophysial portal circulation following stimulation of the HPA axis, where it stimulates the release of adrenocorticotropin hormone (ACTH) from the anterior pituitary. ACTH stimulates the adrenal cortex's release of glucocorticoids once it enters the systemic circulation. Cortical regions also contain a lot of CRF-containing neurons, which may play a role in facilitating both behavioral and cognitive responses to stress. CRF neurons are also abundant in the amygdala's central nucleus, which is responsible for processing emotional responses.As a result, affective stress responses may be influenced by CRF. The brain stem nuclei, which contain the noradrenergic and serotonergic projections of the locus ceruleus and raphe nuclei, respectively, have also been found to contain corticotropin-releasing factor neurons. As a result, CRF may exert both depressant and anxiolytic effects by modulating monoaminergic neurotransmitter systems that appear to be involved in the pathophysiology of mood and anxiety disorders.

Our studies' findings are summarized in this review, which also includes previously unpublished data. The implications of our findings for future research directions and clinical practice are further discussed. Our findings, to put it succinctly, suggest that childhood trauma influences depression's neuroendocrine features, likely indicating stress-related risk rather than disease correlates. We propose that the primary lesion after childhood trauma is located at the neural systems level and involves the failure of a connected neural network to adapt or compensate in response to challenge, resulting in exaggerated responses of physiological outflow systems and altered behavior. This is based on an integration of our HPA axis data with findings from affective neurosciences.