Developmental Traumatology: Neurobiological Development in Maltreated Children With PTSD

Developmental traumatology research is the systemic investigation of the psychiatric and psychobiological impact of overwhelming and chronic interpersonal violence on the developing child. This relatively new area of study synthesizes knowledge from an array of scientific fields including developmental psychopathology, developmental neuroscience, and stress and trauma research. Child maltreatment experiences-defined as neglect, physical abuse, sexual abuse, and witnessing domestic and community violence-are increasing in the United States and may be the most common causes of interpersonal traumas and posttraumatic stress disorder (PTSD) in children and adolescents (DeBellis, 1997).

Childhood is a unique and progressive period of physical, behavioral, cognitive and emotional development. The brain and its biological stress systems are genetically programmed to be influenced by early experience. Trauma involves both traumatic experiences and developmental consequences (Pynoos et al., 1995). Child abuse experiences may cause delays or deficits in a child's ability to achieve age-appropriate behavioral, cognitive and emotional regulation. Traumatic consequences include the signs and symptoms of PTSD, such as intrusive re-experiencing of the trauma, persistent avoidance of traumatic triggers, numbing of responsiveness and persistent symptoms of increased arousal (APA, 1994). Traumatic stress may have negative effects on the development of biological stress systems, perhaps leading to the various types of psychopathology commonly seen in abused children (Cicchetti and Lynch, 1995; DeBellis and Putnam, 1994; Perry, 1994).

One active area of developmental trauma research involves the effects of maltreatment on major body stress response systems such as the hypothalamic-pituitary-adrenal (HPA) axis and the catecholamine system (the locus ceruleus-norepinephrine/sympathetic nervous system), and on brain maturation (DeBellis et al., 1999b). This article will review evidence suggesting that child abuse may be associated with alterations of the body's major stress systems. Adverse effects on brain development will also be reviewed. The clinical implications of these alterations will be discussed.

There is little research on the neurobiological effects of trauma and PTSD in developing children. Results from recent research at the University of Pittsburgh's Western Psychiatric Institute and Clinic's developmental traumatology laboratory suggest that the overwhelming stress of maltreatment experiences in childhood are associated with alterations of biological stress systems and with adverse influences on brain development (DeBellis et al., 1999a, 1999b).

In one study, 18 prepubertal maltreated children with PTSD and 10 nontraumatized children with overanxious disorder (diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised) underwent 24-hour urine collection for measurements of urinary-free cortisol (a reflection of HPA axis regulation) and urinary catecholamine excretion. Their results were compared with those of 24 healthy controls. Maltreated subjects with PTSD excreted significantly greater amounts of urinary-free cortisol and catecholamines than did nonabused controls. These biological stress measures correlated positively with the duration of the PTSD trauma and with PTSD's symptoms of intrusive thoughts, avoidance and hyperarousal (DeBellis et al., 1999a).

In a second study, 44 maltreated children and adolescents with PTSD and 61 matched controls underwent comprehensive clinical assessments and anatomical magnetic resonance imaging brain scans. Maltreated subjects with PTSD had 7% and 8% smaller intracranial and cerebral volumes, respectively, than matched controls. The total midsagittal area (the major interconnection between the two hemispheres that is conceptualized as facilitating intercortical communication) and the middle and posterior regions of the corpus callosum were smaller in abused subjects.