How to break up with a girl who is extremely emotionally attached to me?

[ɨ♥мy♥ԍғ♥]

Talk to her! Just get her to sit down for a seriously heart to heart talk and explain everything you told us here to her (and more if you have to and make sure she know this is a serious talk). Explain your situation and how you feel about it. Make her understand where you are coming from.

I am not a Psychiatrist nor i been in this situation, if you think she has mental disorder or issue, best to talk her parents about it and let them know what's going on with their daughter and they can keep and eye out for her. Maybe even seeing a counselor or even a Psychiatrist (if necessary), just to help her sort herself out.

If she doesn't listen or stay the same (and maybe refuse to seek help), maybe you should just consider breaking up with her. But before you do, make sure you change ALL the password to all your accounts that she has access to before you break up with her (if any of your accounts have security/recovery questions, change those too). So might change all your password as revenge and hold your accounts hostage (not saying she a bad person, but you have to be wary of this might happen).

Good Luck