Tetris helps but the same can not be said of all games.
A team of researchers from Oxford University have conducted additional research into the theory that Tetris can help prevent people from developing PTSD. Post-traumatic Stress Disorder is an anxiety disorder that can affect those that have suffered through traumatic psychological events and is not uncommon among troops returning from war. Overcoming PTSD is difficult but a study in 2009 showed that Tetris helped when played after experiencing trauma. This led Dr. Emily Holmes at the University of Oxford's Department of Psychiatry to investigate as to whether the same could be said of all computer games.
The study chose the computer game Pub Quiz to compare against Tetris' ability to reduce the effects of PTSD. According to the study, participants viewed traumatic footage of death and injury before completing one of the following tasks: Playing Tetris, playing Pub Quiz, or doing nothing (control group). The participants flashbacks to the traumatic events were then monitored for one week.
The researchers found that playing Tetris half an hour after viewing the film reduced the number of flashbacks experienced when compared to the control group. Interestingly, Pub Quiz led to an increase in flashbacks experienced after this experiment.
The second experiment showed that playing Tetris four hours post-film also reduced flashbacks when compared to the no-task group. The Pub Quiz did not reduce flashbacks in this experiment, nor did this group experience significantly more flashbacks than the control group. The study also found that when asked one week later, members of each group all had comparable scores on a recognition test based on the video they had seen, meaning Tetris didn't interfere with their memories of the film, just the formation of flashbacks.
The study says Tetris or another simple visuospatial task may act as a 'cognitive vaccine' that inoculates against the build-up of flashbacks by interfering with formation. What's more, researchers say that because the beneficial effects of Tetris are retained at four hours post-trauma, there's a feasible time-window to administer this "cognitive vaccine" post-trauma.