Sagging Headliner

My headliner's been sagging now for a while and it's starting to bother me. It's not just the cloth portion, but the hard backing too. There is only one spot where it does this and I'm afraid it has to do w/sunroof. It sags at the far back, though not at the edge, in the middle, right above a person in the middle-back seat. It dips down about 2 inches at peak sagging w/diameter of maybe 1/2 foot. When I try to push it up, it will go up as long as I press. As soon as i let go, it pops back. Is that where the sunroof motor components are located? Could driving at highspeeds (95 mph) with the sunroof open cause this?

old age, heat, water, being rubbed against, these things can cause it to sag. id say its time to rip it off, and recover it. anytime a headliner sags, thats the best thing to do because the foam can hold odors and will fall apart over time.