Crack in sheetrock

[shinmin]

What causes cracks in sheetrock?
How do you fix it?

Thanks.

[woodall83]

You better call an engineer. No one here can give you a positive answer without seeing it.

[CThomp]

Lots of things can cause a crack in drywall.

I'd cut that section of drywall out first. Nothing will go wrong and you need to fix it anyhow.

It could be:
settling
failing
bending
sagging
rotting
or
old