Stress and brain development

Stress Brief periods of moderate, predictable stress are not problematic; in fact, they prepare the child to cope with the general world. The body's survival actually depends upon the ability to mount a response to stress (Shonkoff & Phillips, 2000). But prolonged, severe, or unpredictable stress-including abuse and neglect-during a child's early years is problematic. The brain's development can literally be altered by these experiences, resulting in negative impacts on the child's physical, cognitive, emotional, and social growth. Chronic stress sensitizes neural pathways and over-develops certain regions of the brain involved in anxiety and fear responses, and often results in the under-development of other neural pathways and other regions of the brain (Shore, 1997). Children who experience the stress of physical or sexual abuse will focus their brains' resources on survival and responding to threats in their environment. Children who experience the chronic stress of neglect-e.g., remaining hungry, cold, scared, or in pain-will also focus their brains' resources on survival. This chronic stimulation of the brain's fear response means that the regions of the brain involved in this response are frequently activated. When they are, other regions of the brain, such as those involved in complex thought, can not also be activated and are therefore not "available" to the child for learning (Shore, 1997). Because the brain ultimately controls all bodily functions, experiences that alter brain development also alter our bodies' responses. Studies have shown that "… the overwhelming stress of maltreatment experiences in childhood is associated with alterations of biological stress systems and with adverse influences on brain development" (DeBellis, et al., 1999). One example of the effects of early maltreatment on brain and body functions involves the chemical cortisol. Cortisol is a hormone that helps the body prepare to cope with stress through its effects on metabolism and the immune system (Hart, Gunnar & Cicchetti, 1995). Studies have shown that many infants and children who have been maltreated have abnormal secretions of cortisol, indicating that their bodies' responses to stress have been impaired (Hart, Gunnar & Cicchetti, 1995; Lott, 1998, citing Main, 1996). More research is needed to understand why this occurs and what effects this may have on the children's emotional and social development, but this information provides some evidence of altered brain activity in maltreated children. A key issue in understanding altered brain development in children who have been maltreated is that the way in which their brains develop is often a very adaptive response to their negative environment, but it is maladaptive in other environments (Hart, Gunnar & Cicchetii, 1996). If a child lives in a threatening, chaotic world, his brain will be hyper-alert for danger; his survival may depend on it. But if this environment persists, and the child's brain is focused on developing and strengthening its strategies for survival, other strategies may not develop as fully. If a child lives in a world that ignores him, if he is not provided with appropriate stimulation for growth, his brain will focus on survival from day to day and may not fully develop healthy cognitive and social skills (Ounce of Prevention Fund, 1996, citing Lieberman & Zeanah, 1995). The result may be a child who has great difficulty functioning when presented with a world of kindness, nurturing, and stimulation. It is an unfamiliar world to him; his brain has not developed the pathways and the memories to adapt to this new world.