The biological causes, are the easiest to talk about, because there is not much to say.
Many biological factors have been nominated as candidates for causes of violence. Hormones like testosterone, transmitters in the brain like serotonin, and blood abnormalities like hypoglycemia are only a few that have been mentioned.
Biological factors do not have to be hereditary. They could be caused by a head injury, poor nutrition, or environmental events, such as exposure to lead paint.
Fortunately, the National Academy of Sciences just reviewed hundreds of studies on the relationship between biology and violence, and it came to one clear bottom-line conclusion: " No patterns precise enough to be considered reliable biological markers for violent behavior have yet been identified." The National Academy of Sciences found many promising leads that should be vigorously pursued by researchers, but so far, it could point to nothing as a proven, or even close to proven, biological risk factor for future violence.
In conclusion violence can have many causes, one of them being biological causes. People could turn violent for injury, poor nutrition or enviornmental events not necesarily hereditary.
