This might not be directly related to video games, but this article analyzes the impact of virtual worlds, specifically the internet on our mental health. Clinical psychology is still improving, but there have been replications of studies that suggest a kind of "media psychosis" is indeed possible, and we should not dismiss it so easily.
*Just a note, clinical psychology is not perfect so please don't be offended if you think differently from the article.
Is the Web Driving us Mad?
(article sent to me from Tissyana Camacho)