I don't know if this helps. I'm very smart but have a benign brain tumor, epilepsy, and am on epilepsy meds. I also have always had a melancholic streak.

I hated school with an undying passion. I loved learning. I loved the idea of learning. I even liked starting school each fall. I hated school. It was a big boring, socially excruciating, mentally and physically exhausting pain. You had to get up at crack-o-dawn thirty, have people tell you what to do all day long, and get picked on. Teachers just nagged me constantly, and all I wanted to do was be left alone. I just can't tell you how miserable it was. I loved band, which I was very serious about, and enjoyed AP English. That was pretty much it.

Now, as an adult with a masters degree, I can tell you that HS was a complete waste of time, and a dehumanizing experience. I tried substitute teaching, and as big a waste of time HS was for me, it is REALLY a waste of time for them. There is nothing going on. (At least at the schools where I was.)

I don't know what you can take from that, or if your daughter feels at all the same. I guess I'm just saying that your daughter may be consciously or unconsciously avoiding pain and agony. That's not an excuse for being irresponsible, or making it a pain for you, but it might help to know if she is going through something like that.