i know a really heavy one, called "a child called it" by dave Peltzer.
its a really horrific biography of a child who gets abused by his mother
but it is very confronting.
so i wouldnt take that book on lightly.
if your looking at last minute stuff, id suggest and image( cartoon, photo) , as well as a poem.
they are much easier to analyse in a short amount of time than a novel!
umm..
i cant really thinkof another text at the moment,
sorry!
goodluck