The Use of Imaging Technology and Physiological Measurements
Michael D. De Bellis, M.D., University of Pittsburgh
Maltreatment of children is increasing in the United States and may be the most common cause of interpersonal traumas and posttraumatic stress disorder (PTSD) in children and adolescents. Developmental Traumatology, the systematic investigation of the psychiatric and psychobiological impact of overwhelming and chronic interpersonal violence (maltreatment in childhood) on the developing child, is a relatively new area of study that synthesizes knowledge from an array of scientific fields including: developmental psychopathology, developmental neuroscience, and stress and trauma research. One active area of research involves the effects of maltreatment and related stressors on major body stress response systems such as the hypothalamic-pituitary-adrenal (HPA) axis, the catecholamine system (the locus ceruleus (LC)- norepinephrine (NE) /sympathetic nervous system (SNS)) and the immune system and the subsequent effects of chronic stress on brain development. To investigate these relationships, researchers at Western Psychiatric Institute and Clinic have begun to gather data using physiological measures to capture changes is the stress response system. To capture changes in brain development, imaging technology is being used, which provides a non-invasive way to examine differences in brain morphology and physiology.
Results from recent research at the Institute's Developmental Traumatology Laboratory suggest that the overwhelming stress of maltreatment experiences in childhood is associated with alterations of biological stress systems and with adverse influences on brain development.
In one study, 18 prepubertal maltreated children with PTSD and non-traumatized children with DSM-111-R overanxious disorder (N=10) and healthy controls (N=24) underwent 24 hour urine collection for measurements of urinary free cortisol (UFC), a reflection of HPA axis regulation, and urinary catecholarnine excretion. Maltreated subjects with PTSD excreted significantly greater amounts of UFC and catecholamines than non-abused controls. These biological stress measures correlated positively with duration of the PTSD trauma and symptoms of intrusive thoughts, avoidance, and hyperarousal.
In a second study, 43 maltreated children and adolescents with PTSD and 61 matched controls underwent comprehensive clinical assessments and an anatomical magnetic resonance imaging (MRI) brain scan. Maltreated subjects with PTSD had 7.0 % smaller intracranial and 8.0% smaller cerebral volumes than matched controls. The total midsagital area of corpus callosum, the major interconnection between the two hemispheres that is broadly conceptualized as facilitating intercortical communication, and the middle and posterior regions of the corpus callosum, were smaller in abused subjects. In contrast, right, left, and total lateral ventricles were proportionally larger than controls, after adjustment for intracranial volume. Intracranial volume robustly correlated positively with age of onset of PTSD trauma (i.e., smaller brains were associated with earlier onset of trauma) and negatively with duration of abuse. Symptoms of intrusive thoughts, avoidance, hyperarousal and dissociation correlated positively with ventricular volume, and negatively with intracranial volume and total corpus callosurn and regional measures. The decreased hippocampal volume reported in adult PTSD was not found in these subjects.
These data suggest that chronically maltreated children with a diagnosis of PTSD manifest alterations of major biological stress systems including adverse influences on brain development. Although based on a cross sectional analysis, and thus causation cannot be proven, these findings are intriguing and may have important social policy and treatment implications. Elucidating the biological sequelae and mechanisms of symptom production in PTSD and associated comorbid psychiatric disorders will pave the way to better clinical and social treatment of abused children. Accordingly, prospective longitudinal studies in Developmental Traumatology are critical to the effort to develop early interventions to attenuate the psychobiological dysregulation and adverse effects on brain development associated with maltreatment.
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