Borderline personality disorder vs. sociopathy

This was an interesting article from the Psychology Today blog relating an experiment done examining the brain activity of sociopaths and comparing it to that of people with borderline personality disorder. Why these two disorders? Apparently, sociopathic and borderline traits occur with equal frequency among violent offenders, but they reach their antisocial behavior in different ways:

Typically, antisocial offenders with borderline personality disorder are emotionally reactive, unable to regulate emotions, bereft of cognitive empathy (knowing how another person feels), rageful, and reactively aggressive. By contrast, antisocial offenders with high psychopathic traits can be characterized as emotionally detached, cognitively empathic, morally problematic, exploitative, and proactively and reactively aggressive.

The experiment:

The investigators took MRI scans of the two groups of antisocial offenders, with the aim of exploring differences in the cerebral structure of their brains. All offenders had been convicted for capital, violent crimes (including severe bodily injury such as murder, manslaughter, robbery, or rape) from high-security forensic facilities and penal institutions and were formally diagnosed with antisocial personality disorder. There was also a comparison group of healthy men.

The results:

The antisocial offenders with borderline personality disorder had alterations in the orbitofrontal and ventromedial prefrontal cortex regions, which are involved in emotion regulation and reactive aggression; there were also differences in the temporal pole, which is involved in the interpretation of other peoples’ motives. By contrast, the antisocial offenders with high psychopathic traits showed reduced volume mostly in midline cortical areas, which are involved in the processing of self-referential information and self reflection (i.e., dorsomedial prefrontal cortex, posterior cingulate/precuneus) and recognizing emotions of others (postcentral gyrus). 

I thought this was interesting. I wrote previously about the connection between sociopathy and alexithymia, or the decreased ability to identify, understand, and describe one's own emotions. This trait has been linked to a lack of empathy, the idea being that if you are unable to understand your own emotions, you don't stand much of a chance of understanding the emotional worlds of others. I feel like I don't understand my emotions, that they feel out of context to me, like I'm getting only snippets of a movie played backwards. This feeling probably contributes to my weak sense of self. This brain scan study seems to comport with this theory -- that sociopaths suffer from an ability to process self-referential information and to self-reflect, and that consequently sociopaths have flexible understandings of not only morality, but basically every human trait.