or even forming "normal" social bonds

When you say this, what do you mean? Psychopath's will form bonds. Not real bonds. But bonds nonetheless to gain something for themselves. They will come off as charming and social but when they are done using a person they will toss them aside like the nothingness the psychopaths think they are.

Anyway with that aside-

Why not Monster? Have you read it? And if so, what about it(more specifically Johan,) is not psychopathic? Just wondering as I kept thinking why someone would doubt that he is. (Except maybe what he said about his sister.)

This might be a longshot, especially since this is shounen action, but what about Hunter x Hunter.

These aren't main characters, but are antagonists.
Hisoka, appearing in the first few books, then again in later arc. Is a person who kills without remorse (psychopathic clown). But has his own morals about who is 'worthy'. And prefers to fight strong characters. (But will easily kill a person who bores him)

But more interesting to you might be the characters in the Genin Ryodan (sp?) arc. They are group of bandits who kill easily, and care little about anyone outside of their group. They are lead by Kuroro, who dreams of revolutionary anarchy.

AGAPE -- seriously, the mangaka claims she "loves everyone equally" but it just seems like she doesn't really care about anything at all. I did not understand this mangaka's thought process when s/he was creating this. This has what you want though, since she's not homicidal or muderous, she has no social bonds and she is generally just kind of disturbingly apathetic. Technically the mangaka touts it as "extreme empathy" but if you read it, it really doesn't seem like that At all.

Shamo
But it's a really strong manga, starting when a young guy kill his parents. And how jail builds up his character, and how he sees things from his point of view.
It's the darkest seinen i've ever read...
The guy really doesn't give a shit about anything that happens to people near him, or how many lives are crushed as a consequence of his actions.

But it has some homosexual rape and gore on the first volume, that drives lots of people away from the manga, but that doesn't happen again. It's far away from being a gay manga.

It's a fighting manga pretty realistic on the first volumes. Then for a while it shows some powers in a volume, and goes back to normal fightings.
If you are up to this kind of thing, give it a try, you'll love it.

Drifters might fit
World Embryo might also fit

vision of escaflowne yup some characters here are psychos but i suggest seeing the anime . It rocks!

Mirai Nikki

domu

[img]http://i572.photobucket.com/albums/ss162/westsiders2/Signatures/comicsigcopy2.jpg[/img].
http://westsiders2.deviantart.com/

Quote from dark mage

Mirai Nikki

if youre thinking of yuno gasai, shes not a psychopath / sociopath, she has borderline personality disorder / emotionally unstable personality disorder, but there are a few minor characters that are...

its nice to see someone asking for something and being really descriptive about it.... then getting a bunch of responses that dont have anything to do with what he / she wants... not that i can think of anything either

thanks for linking Trick Ster! really good manga, love the art too

How about Dr. Frost?

Tokyo Babylon has a chapter with 3 characters who could be seen as psychopaths/sociopaths (in the sense of npd/aspd) and are not treated as stereotypes. They're treated in a way that shows them more as humans and is very sympathetic about it.

Mother Keeper isn't as forward about it, but one of the characters does come across as a psychopath, and once again isn't treated as some big monster. He does form a bond with someone but it takes a long time and tbh it's very good handling it. The manga isn't especially pretty at first and the original translators were very much slacking, but the art improves greatly and it later gets translators who actually tried.

its not nearly as apparent as the rest of these recommendations but i think

Cheese in the Trap fits pretty well.
link here
its kind of a spoiler so ill put it in as one

you dont really see it at the beginning because he hides how he really feels about others pretty well but it gets more and more obvious that he has problems throughout the story, i dont know if i would call him a sociopath but he definitely gets close at some points and once the MC finds out about these moments she does not understand him and fears him. it also fits with how you wanted them to not be able to connect with people. he is really popular at school but he never thinks about any of them as friends and has a lot of problems connecting with the MC also.

[img]http://24.media.tumblr.com/3b280fafb72cad0f718be64368e64ca7/tumblr_myylzmuiY41rw3pzao4_250.gif[/img]
Like educational manga? take a look at Ed U. Manga's list of manga here

Sorry for being so late, but I think you would like Kami no kodomo. For more info: https://myanimelist.net/manga/24808/Kami_no_Kodomo

Hello! (My first post here...but no one rly cares). I've read bastard(hwang youngchan) and I really liked it. Although is not very popular you can find the manga in most of the mangawebsites.

The story is about a boy whose father is a psycho serial killer and since he was a child he helped his father covering the tracks and killing the victims. The story has an interesting plot development(in my opinion) and may be what you are looking for.
Another manga that I was superb in my opinion was Monster! It's woth checking out! ! It follows the story of a doctor that saved a kid's life. This Kid is a psycho produc of experiments in the world war II that as a twisted perspective of life and is around making peoples life miserable.

I hope this helped! Good reads!

While I haven't read the manga classroom of the elites main character is very systematic you could say, as he always has an ulterior motive and a messed up past, I doubt he would mind hurting someone or being hurt. The anime leaves you on a cliff hanger though. (Classroom of the elite) ?