Okay, that title’s not especially politically correct. I think the rest of my post is, though, so humor me. Household abuse is an interesting topic to apply neuroscience to, and I found a nifty article on the subject! It even ties into our drawn-out Nature vs. Nurture debate. So you don’t have to read it yourself, here’s a synopsis:
There were startling statistics. 20,000 annual deaths in the US from homicide and 4.2 violent crimes/100 people per year. Ouch. Seems like it’s gone down a bit since then (then being 1999, since you’re not reading the article), which is probably a good sign. Same ballpark, though.
34% of “risk of violence self-reported by community residents” stems from substance abuse, and apparently a lot of that is alcohol. Type 2 alcholism is the cause. I did a bit of extra research, and apparently Type 2 is characterized by an antisocial personality disorder, are likely become alcoholics at a relatively young age, are generally male, and are thought to be influenced (either genetically or culturally) by their fathers. Nature vs. nurture indeed! Consistent with that, children abused by their parents have a 33% chance of becoming abusers themselves. Judith Harris, your theory is not entirely supported by this statistic. Epigenetically, Fetal Alcohol Syndrome contributes to violence in adulthood, as does early maternal rejection.
Serotonin plays a role in regulating aggressive behavior, which I expect you guys know. What’s a bit more subtle is that a serotonin synthesis-rate-lowering gene (tryptophan hydroxylase genotype) is correlated with higher levels of aggression. That means that low serotonin levels (however they’re created) are a major risk factor for violence (and abuse).
The article also discusses the role of the hippocampus and amygdala (smaller hippocampus, bigger amygdala = fury) and the prefrontal cortex (lower glucose metabolism in murderers). They conclude, though, that there are two different things that tend to contribute to violence: rearing environment or morphological dysfunction.
Oh snap. The answer to Nature vs. Nurture here isn’t “both,” it seems to be “either!” Which isn’t to say that they wouldn’t have additive effect; it just seems that either is sufficient for the exigent behavior. Go figure.