Well, I take quetiapine everyday and the times I've crushed it I realized that it takes a little more to make the effect, I don't know if that occured because I was mixing it with food, but for me it doesn't work as I wanted to. Generally when I crush pills, no matter which substance is, it works normally.
If I'm thinking right, you think about doing this because probably the pill is too big, right? Where I live, quetiapine pills increases size according to the dosage and I don't like to swallow big pills as well. If this is the case, I recommend that you break the pill in half and swallow the two halves.