This infographic, provided by Edusson.com explains, what those doodles students usually draw really mean. Teachers, as well as students rarely pay any attention to what is being drawn in textbooks, notebooks or even on desks. And that is the problem, because in reality, they should. Sometimes some serious problems or disturbances are hidden in those small harmless doodles.
This is not some universal guide to understanding pictures of students. It is just a small amount of information on this topic. A lot of writing has been done around this and this is just a small piece of it. It may give you an idea of what your friend/student/relative or even yourself is going through so you could help him.
Original text: link