Hello, welcome to PC!
From what I've experienced, depression is totally isolating. It's really an unfamiliar territory and you'd feel like running away from it. Maybe your daughter tries to fight it by latching on to the familiar, things that once defined her. So a change maybe caused her too much fright... that's what I think.
I'm sorry she's going through this. I can't imagine what it's like from a caregiver's POV. Have you taken her to the pdoc? Is she taking medications?
Hang in there. Sending hugs your way.
__________________
"The is no better exercise for the human heart than reaching and lifting others up." - John Holmes
herethennow: This ward is a prison!
Wardmate: No.. here's not a prison. *points to brain* Here is.
dx: recurrent MDD.