Stress produces cortisol which has shown to damage the hippocamus. Most of the death row inmates she interviewed with both severely physically and psychologically damaged. A large portion of the book deals with material unearthed during the death-row inmate interviews. She believes, as do others, that the type of crime as well as its modus operandi leads an astute investigator to determine the type of pathology involved. Perhaps, even the trauma suffered by the perpetrator decades earler can be learned.
Many murderers are psychotic.
One mother taught her son the art of cunnilingus at age six. Neurological deficits can also sometimes be a cause of the violent and anti-social behavior. One case recounted traumatic forceps delivery and others brain damage because of oxygen deprivation at birth. Psychological results of birth trauma are not discussed. In many of her investigations she was accompanied by neurologist, Jonathan Picus.