i agree with this. i just had the same experience but with a wall, not ceiling.
i hit a cement and had to buy masonary drill bits (the silver ones). but for additional precaution, i also used concrete nail to punch a deeper hole from the part where my initial drilling stopped. then i worked from smaller drill bit to bigger ones.
kind of a crude way, but it worked for me. oh, and try to do your drilling in the daytime or you'll get an earful from your neighbors.
hope this helps.