My long-term gf a neuroscience and experimental psych M.S., another close friend a PhD in the area (jeez...humbling!!). A lot of times it manifests itself as sort of an antisocial or anti-physiological sort of thing because it itself IS antisocial and antiphysiological (physically harmful). There are a lot of theories as to why, but the brain is sort of subversive in these sort of malleable processes. It's weird
AFAIK there isn't much of an answer except that the brain, when not functionally operative, interprets social cues as negative and somewhat threatening (like any of us if we were really confused, like a lot in Alzheimers and such). Basically if the brain doesn't understand it, it's sort of threatening. IOW, the jury is still out. It is absolutely fascinating, I followed my lovely lady through her thesis and I love this wild stuff (now her turn on my thesis....) but its really ultimately a mystery. I thrive on this stuff. I'd take Anthony's opinion over mine though, being closer to the practicing side.