Unable to sleep, Gail Nichols spent a lot of time in front of PopCap’s Bejeweled, a game notable for its non-competitive, flow–inducing modes. According to the Washington Post,

Nichols liked the game so much that she got in touch with the manufacturer, PopCap Games. The inventors of the game were surprised to hear about its possible mental health benefits, and the company decided to study Bejeweled’s untapped potential systematically. In a preliminary study that PopCap commissioned and funded, researchers found that volunteers who played Bejeweled displayed improved mood and heart rhythms compared with volunteers who weren’t playing. The preliminary study was published this year in the Annual Review of Cybertherapy and Telemedicine. Now, the company is about to launch a second phase of testing to see if the video games can have measurable effects on clinical markers of depression.

For the study and related material, see Chapter 44 (pp 189–191) in the Annual Review of Cybertherapy and Telemedicine (2009).