The "-itis" suffix means that something is characterized by inflammation (e.g., bronchitis, tendinitis). So cartoonitis is more likely to mean an inflammation of cartoons rather than an addiction to it.
A more appropriate suffix would be "-philia", which means an obsessive love of something. Bibliophilia, for example, is an actual-factual term for "love of books". :) And logophilia? That's a love of words!