Can watching too much tv or playing to many video games alter your perception of reality?   stance: yes:
yes. say that you only get your news from "fox news" and no where else, they put on wrong statements(such as labeling a congressional republican sexual predator as a democrat) and never make a correction. you now beleive that the sexual predator was a democrat congressman, your reality has been altered.
but thats just a factual reality and can be easily remedied, i suppose the question meant as in making a person schitzophrenic or dillusional,