The total distraction of an addictive video game like Tetris may have a surprising health benefit: preventing post-traumatic stress disorder, or PTSD.

Emily Holmes, Ph.D. and Catherine Deeprose, Ph.D., of the Department of Psychiatry at the University of Oxford, England, found that people who play Tetris after viewing traumatic material have fewer flashbacks to disturbing memories. In their study, 40 healthy volunteers watched a film that included various types of traumatic images, such as the harmful effects of drunk driving (a recognized way of studying the effects of trauma in the lab). Thirty minutes later, half the participants played Tetris for 10 minutes, while the other half did nothing.

The results? The volunteers who played the game reported significantly fewer flashbacks over the following week.

“We know there is a period of up to six hours in which it is possible to affect certain types of memories that are laid down in the human mind,” says Deeprose. She explains that it’s possible to interfere with the way memories are retained in the brain without decreasing the ability to make sense of the event. In this study, the negative memories were disrupted by Tetris, which reduced the likelihood that those memories returned through disturbing and involuntary flashbacks.

For more on this innovative way to heal trauma, go to “Thwack” on page 55.