Does the comics change kids and adults' behaviors and personalities?

Reading in itself is never harmful. Reading broadens the mind and improves the vocabulary. That said, anyone who reads instead of doing things that need to be done are not making healthy choices. If the behavior of the child or adult has recently changed, and they have started reading comics (or doing anything else) as a way of escaping from the world, then they might be depressed. A person who has an unexplained personality change should be evaluated by a doctor anyway, because some of the other things that can cause personality change include drug abuse and brain tumors.