What's that movie where there's an amnesia twist and she's the killer?
I watched this when I was a kid, before 2012 I believe but I can't think any more detailed than knowing I wasn't in high school yet.
Main character is a young woman, probably 18ish because I remember she went off to university. I think it's set in America. Something happened in her past and the movie seemed to lead us to think it was her [sister? friend?] And this person might have been at university with her. She visits home and I think she argues with family about what happened. Things are murky and there's a dramatic reveal that either the friend was never real or she repressed something major. Turns out either she killed someone, someone never existed, or the university was actually a psych ward maybe?
I don't think this movie is very famous, I've never seen it since. I'm English and I think I would've watched it one night on the horror channel, syfy, or film4.
I realise this is all very vague, I'm sorry. This is all I can remember.