Gail Nichols has suffered from depression for years. When the 49-year-old resident of St. Marys, Kan., cannot sleep, she falls back on a form of entertainment that is gaining increasing credibility as a medical intervention: video games.

Nichols said she discovered the mental health benefits of video games some years ago during a bad spell of depression. She had just started playing a game called Bejeweled, which requires players to move gems into rows based on their color. When she could not get to sleep one night and was tormented by mental pain, she said, she turned on the computer and played the game for hours.

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, 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.

The research is part of a broad array of unconventional efforts that video game companies are devising to find new markets for their products. Many of these steps are based on the idea that depression and other disorders — as well as everyday stress and worry — involve systematic patterns of thought and self-doubt, and that games can distract people and put them in a different mental zone.