Maybe D&D is part and parcel of the effect of one's psychosis, not the cause however.
D&D is a ROLE PLAYING GAME ... and as such whilst 99.9% of it's players are healthy, or stable is perhaps a better term, people (well, psychologically at the very least). The problem lies in that D&D is a high fantasy adventure that requires a concerted effort on a part of the DM and the players to recreate a mythical surrounding that has characters who are inundated by the pervasive magical nature of the surrounds that their 'campaign' takes places.
SO D&D wouldn't create the psychopaths, but naturally speaking it might hold a great appeal to people with fantasy prone disorders, or dissociative neuroses.
What people forget is that most nutcases are BORN nutcases ... people who say D&D/video games kill are largely idiots.
Yes I believe a psychologically unsound environment can produce killers ... but to say video games/games in general kill is like saying "Newton created Gravity" ... no the forces of gravity were always there ... and it takes a human to try (in this case horribly) to put the pieces together.
Not only this, but why is people blaming games when this article already shows she was out of her MIND ... she killed her brother. WHAT THE HELL? Yes ... D&D .... Or maybe Her + Weapon = Rampage.
Though I am generally interested by this article ... it's not usual for women to be not only serial killers, but also spree killers.