Brain Effects

When the developing brain experiences stress, the increased activity of neurotransmitters and hormones affects total brain development. Childhood sexual abuse may result in significant damage to the brain during its development stage. A cascade of hormones and neurotransmitters is released as a result of stress. Resulting damage includes: degeneration of neurons, neurochemical abnormalities, neuroendocrine disturbances, and alterations in the structure of the brain. The release of high levels of glucocorticoids harms the hippocampal formation (Weber & Reynolds, 2004). Repeated stress results in a chronic neurochemical process causing homeostatic failure. The system cannot return to a non-stressed status, and limbic system hyperarousal is common.

Neurobiological findings link childhood trauma, dissociation, Posttraumatic Stress Disorder (PTSD), and somatic symptoms. In reviewing the literature, Diseth (2005) found evidence of permanent trauma-related neurochemical and functional changes in the brain. These findings clarified the cerebral mechanisms involved in trauma and dissociation and the subcortical processes linking these to PTSD and somatic disorders.
Studies show that PTSD results in neuroendocrine and neurochemical alterations and structural brain changes. Some of these changes include decreased levels of cortisol, increased responsiveness of glucocorticoid receptors and high glucocorticoid levels; increased sensitivity of HPA negative feedback inhibition; increased excretion of noradrenalin, adrenalin, and dopamine; increased noradrenaline following stress; abnormal catecholamine activity; abnormal arousal mechanisms in the sympathetic nervous system; abnormal hemispheric laterality; altered dopaminergic functioning; elevated cortisol;reduced immunosuppression; increased release of aminopeptide; increased release of ACTH; alterations in serotonergic metabolism; reduced volume in the hippocampal region; hyperresponsivity in the amygdala; and altered function in the limbic region (Brunello et al., 2001; Horner & Hamner, 2002; O’Donnell et al., 2004; Pappas, 2000; Weber & Reynolds, 2004). Changes occurring in the benzodiazepine and opiate receptors of the brain may affect the person's ability to self-soothe and to enjoy life or increase susceptibility to drugs of abuse.

Results from a study by Girdler et al. (2003) suggest that the stress of even one traumatic abuse incident results in ongoing alterations in sympathetic and HPA axis responsivity to stress. Increased cortisol present during stress increases the presence of glucose, interfering with the function of the hippocampus and resulting in damage.This damage impacts the child’s social skills, impulsivity, and aggression. 

Research also shows that damage occurs when children use dissociation as a coping mechanism. Dissociation is associated with impairment in the developmental process and includes  1) development of neural networks, 2) primitive parasympathetic regulation by the dorsal motor nucleus, and 3) lack of integration of bodily sensations (Panzer & Viljoen, 2004).   

See Stress: Effect on Brain
See Stress: Effect on Body
See Stress: Effect on Immune System


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