cover quickly from injury. While these traits may be necessary in the reproductive years critical to evolutionary success, they come at a price: research has shown the result is an increased risk for obesity, type II diabetes, and hypertension, as well as many different psychiatric problems such as a heightened risk of suicide, and they are also associated with an accelerated aging and degeneration of brain structures such as the hippocampus.
Researchers have found a gene which appears to be activated by abuse in childhood which causes some boys to grow up to be violent or aggressive (Study, 2002). The gene controls the production of monoamine oxidase A (MAOA), which breaks down key neurotransmitters linked to mood, aggression and pleasure. In boys carrying one form of the gene, childhood abuse causes reduced production of MAOA, making them 9 times more likely to be antisocial. As adults, 85 percent of the severely maltreated children who had the gene for low MAOA developed antisocial outcomes such as violent criminal behavior, but those with normal MAOA activity did not develop these problems. The gene is on the X chromosome and therefore its effect is canceled out by the normal version on the other X chromosome in girls.
The brains of patients with a history of abuse are twice as likely to show abnormal electrical activity as people who did not suffer abuse (Crombie, 2003). Right-handed abuse victims show abnormalities in the left side of the brain: left-handed victims have yet to be tested. These abnormalities may contribute to depression and memory problems. Teicher and colleagues have found evidence of anxiety, depression and brain differences in college students exposed to loud yelling, screaming and having belittling remarks directed at them. Research has also shown electrical abnormalities in the brains of abused people similar to those in patients with epilepsy, and some abused patients even have pseudoseizure...