It's interesting, but now I don't know what to do with this information.

If psychopathy is defined by the complete lack of several qualities, such as empathy, remorse, impulse control, etc. it's not a huge stretch to realize that it's either very complicated or utterly impossible to get them to change (aside from the fact that most likely they wouldn't care as such to change). I'm assuming there's going to be some differentiation/variation as to the presence of these traits, so perhaps some people suffering from psychopathy can learn and can improve.

It's just that it would cost an awful lot of time, and the end result would perhaps be a slight improvement. So it's not particularly cost effective.

On the other hand, I know from personal experience that it's possible to learn and train traits. And there are e.g. studies that show that people who suffer from autism tend to become more social after they've turned 30. Not that autistic people are the same as psychopaths, but it shows that conditions rooted in the brain may improve over time.

So probably there is a grey area somewhere. Still, I'd advise anyone to not invest too much time in a psychopath, because they tend to resent the people that are near to them the most, and most likely they will give extra time and effort in making sure that you pay for it.