I know exactly what you mean. I have often prayed every night that God would take me in the night. I have often wished I would get a terminal disease and just die. If I got cancer would I fight it and go through all the chemo, and radiation, and surgery. I don't know if I would. My grandpa got pancreatic cancer at 75 and chose to have no treatments. Everyone was very upset and wanted him to fight it. He didn't have depression or anything but he was very content just to die. I really respected that and understood.

I think of passive suicide as sub-consciously doing self destructive things. Like slowly killing yourself with drugs and alcohol or reckless driving.