It seems to me most research shows a correlation between those who play more video games and risk of suicide but there's no suggestion of causation. It's also really difficult to test for causation in a study because you would essentially need a group of people who have similar traits/factors of those who play video games but don't actually do so. I think there just exists a correlation because whatever factors/traits lead to increase chance of suicide just happen to also exist more often with those who play video games. For example, being introverted or anti-social.