(i do post sometimes, especially since i like finding out potential reasons for why people do things)
i (at the time 16m) dated a girl a few years ago (at the time 15f) who claimed to completely lack empathy. she always talked about how terrible she was and how unlovable she was, and wondered why no one liked her.
when i wasn’t there 24/7, she’d abuse substances, harm herself, and the like. she reported hearing voices, had sleeping issues as well.
she also claims to feel no remorse and outright ghosted me after we broke up. we were friends and she suddenly ignored me when she was 16, i was 17 (female then) and right before we stopped talking i found out she was actually straight, not bi or lesbian, and she would send links to gore websites telling me that they were “funny”, “not that bad”, or that she “didn’t feel a thing”.
Yes, that sounds plausibly like one of several. BPD or bipolar, or just PTSD from abuse, etc. Orrrr something else or a combination. Obviously none of us here can diagnose that, but by the description she has all the signs of a serious mental illness.
That person desperately needs psychiatric intervention. Unfortunately, many people who suffer mental illness fall into such patterns and as adults end up in jail, dead , or homeless.
Above all: dont ever let her pull you into it.