well said (づ￣ ³￣)づ
Wow. All of this story has definitely taken place in under a year. When he met Bum he was a serial killer. He only stopped murdering women lately. I don't know if he'd ever be a "productive member of society" but literally no one has ever offered him help. He has never (so far as we readers are aware) had any type of therapy and it seems has relied on himself since his mother has been gone. I wouldn't give up on someone so completely. I might not leave my kids or myself with him any time soon, but I'd like to think that if he actually sought help (or was offered help and accepted it) and worked at it he might be able to fix some of his issues.
I'm not saying we should give up on offering him any sort of help. My point is that changes that took place in Sangwoo's psyche are too deep and were developed on a biological level (struggle to survie) so I personally doubt that some regular psychotherapy would "cure" him. There are some conditions you just can't cure, which of course doesn't mean we can let people affected by them walk freely on the streets and not care about them, their feelings and what they do.
We all undergo struggle to survive on some basic level. And everything we do is at a "biological level" - those are actions. Unless you're talking about issues that are genetic that would take gene therapy to work on. Some things can't be fixed but he didn't seem to be like this as a child. It seems it ramped up through the years as his mother abused him more and more and was finally out of the picture. He's not necessarily a Ted bundy or John wayne gacy that have childhood serial killer links to their actions (the famous three wetting the bed, animal harm, and starting fires among other signs). Talk therapy and psychiatry may not work, but so far it seems like none of that has even been *tried*. He may have gone his whole life without even seeing a counselor. And of course there's so much we don't know as the author only gives us glimpses through time.
We all do have struggles, but Sangwoo's case is drastically different. Our experiences are very minor compared to his.
I'm bringing up biology because biology actually matters, and genetics isn't the only component. Like e.g. some stessors such as high cortisol levels in fact may alter your brain functioning, also you may experience some disturbances in your amygdala (amygdala controls emotions, mainly negative ones). And it's done through life experiences, not only genes.
Many people say "Sangwoo needs therapy", but I doubt it would help.
Sangwoo can't be "treated", it's not like he only suffers from some childhood trauma and PTSD. Even now, when he finally lives a relatively "normal" life with Bum, he still is unable to get over his past. He literally can't learn how to trust people, anybody including Bum, because he was so deeply betrayed and hurt by his own mother, a person that is supposed to love you unconditionally, that no matter how hard he tries, he's just too much of a mess to forget and start everything over from the very beginning. His ways of "dealing" with his crazy parent, like behaviours that most people under normal circumstances would see as paranoid such as checking how many pills there are left in the bottle, were the reason why he managed to survive through his childhood. So, fun as it is, his psychosis made him live. The thing is, even now in adult life he still uses exactly the same methods to make sure he's safe, when there's no longer need to.
It's very tragic to see how Sangwoo's learnt mechanism of coping with problems that always used to work with his mum now simply seems to fail and makes him go more and more insane every day in addition to only causing him pain and suffering.