A study published in Cerebrum in late 2000 demonstrated that childhood abuse and neglect results in permanent physical changes to the developing human brain. These changes in brain structure appear to be significant enough to cause psychological and emotional problems in adulthood.
Martin Teicher and his colleagues identified four different abnormalities in the brain that were much more prevalent in adult survivors of abuse and neglect than in adults who had not been abused.
Adults abused as children exhibited abnormal development of the left hemisphere of the brain. The researchers reported that these problems may be associated with depression and memory problems.
Abuse survivors failed to integrate the functions of the left and right hemispheres as well as those who had not been abused. The researchers suggest that this may be caused by a decrease in the size of the corpus callosum - the fibers that connect the right and left sides of the brain. There was a difference between males and females in their response to abuse and neglect. Neglect was the more likely factor to reduce the size of the corpus callosum in males, while sexual abuse appeared to have no effect. Sexual abuse was associated with a decrease in the size in females, with neglect having no effect.
Adults who had been abused as children were more likely to experience epileptic seizures caused by changes to the limbic system, a part of the brain that controls emotions. A variety of emotions accompanied these seizures, including sadness, embarrassment, anger, intense laughter without feeling happy, serenity, and fear.
Teicher and his colleagues found that abuse survivors were twice as likely as non-abused to have abnormal electroencephalogram readings (EEGs). The type of abnormality found is reported by the authors to be associated with aggression and self-destructive behavior. Teicher concluded that "the trauma of abuse induces a cascade of effects, including changes in hormones and neurotransmitters that mediate development of vulnerable brain regions." Previous research has shown that stress affects that developing brains of several species of animals. It should not surprise us to find that humans respond the same way.