Here are two articles discussing the benefits of kids playing chess. The cut-off age is 12-years-old. After that, you might as well play checkers :-)
Brain over pawn: Childhood chess studies have benefits beyond the board
The benefits of playing chess for children
This is an interesting read: True past of Oregon man emerging from federal probe. This 'avid' chess player isn't who he says he is. There's only the one mention of chess in the article, but it's still a interesting read. There are lots of other articles about this same case as well - 495 according to google.
Playing and improving at chess means happiness. Read this inspiring article (which notes chess in a list) that talks about how to be truly happy: The Secret to Happiness. This same article also talks about flow.