I have a 5 foot crack in the ceiling of my home office. Also, the crack is in the middle of an area that has bowed down. I measured and the bowed area is 4 feet from the wall, which I think is the standard width of drywall. The crack is approximately 18 inches from the wall, which puts it in the range of the ceiling joists. My worry is that this section will eventually drop completely, onto my computer cabinet, bookcase, and several wall shelves all holding framed photos. Moving the computer cabinet isn't something I can do, even empty. I'm wondering if I can somehow secure the drywall again without removing it.
My home is about 35 years old, brick exterior, built on a slab. I've checked the roof, no evidence of leaks, no cracks in mortar between bricks, no outside damage that would lead to the ceiling problem. Any advice?