Blocking trauma with coloured blocks (Image: Oli Scarff/Getty)

Manoeuvring the colourful tiles of Tetris can help block flashbacks of traumatic events, even after the memory has fixed itself in your mind. Playing the game could be an easy way to reduce the risk of post-traumatic stress disorder (PTSD).

After any event, there is a window of about six hours where memories are consolidated and cemented in the mind, says Emily Holmes at the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, UK. Sleeping on the memory strengthens it further.

If an event is particularly traumatic, vivid memories of it can reoccur. These intrusive flashbacks are distressing for anyone, but in a proportion of cases they can persist and contribute to PTSD. For example, about half of people who have been raped go on to develop PTSD, as do a number of asylum seekers and people who have been tortured. About 20 per cent of people who have been in a serious car accident are affected by the condition.


There are effective treatments for people who are diagnosed with PTSD, but nothing currently exists to help prevent people from developing it in the days and weeks after the initial trauma.

Sleep on it

Holmes and her colleagues think a dose of Tetris could be the answer. In 2009, they showed that playing the game four hours after being exposed to trauma reduced the number of subsequent flashbacks. But getting the game into a person’s hands immediately after they have been raped, for example, won’t always be practical, so the team tested whether it could still work a day later – after the memory had been consolidated and slept on.

The team asked 52 people to watch video footage of distressing events. “They were clips from public safety videos, for example, so they were designed to stay with you,” says Holmes. A day later, the participants returned to the lab, where half of them looked at still images from the footage, a task designed to reactivate their memories of the video. This puts the memory back into the plastic state it was in before it was fully laid down, giving the team an opportunity to modify it. “It’s a bit like hard plasticine that’s a certain shape. When you warm it up, it becomes malleable and you can start reshaping it,” says Holmes.

Those people who saw the stills then spent 12 minutes playing Tetris while those who hadn’t just sat quietly for 12 minutes.

Over the following week, the group that had played the game experienced 51 per cent fewer intrusive memories of the traumatising video than the group that hadn’t. They also scored lower on the intrusive memory section of a questionnaire used to diagnose PTSD.

Visually demanding

Holmes thinks playing a game that requires visual processing like Tetris forms a “cognitive blockade”, diminishing the strength of the visual component of a trauma memory while it is malleable. The result is that you can still remember and describe what happened but the vivid, detailed images that are most disturbing are less easily triggered. Holmes thinks other visually demanding games such as Candy Crush, or different visual tasks altogether, could also work. “We started with Tetris because there is previous research showing that it uses up visual attention,” she says.

There is still a way to go before Tetris can become an established treatment, perhaps by being part of the support given at a police station after a person has been raped or at a detention centre for asylum seekers, for example. But the team is already testing the game in hospital emergency departments on people who have been involved in car accidents.

Checking the “dose” of gameplay required and how long the effect lasts are on the to-do list, but even if the effect is small or short-term it’s worthwhile, says Holmes. “Think of it like hand washing. Hand washing is not a fancy intervention, but it can reduce all sorts of illness. This is similar – if the experimental result translates, it could be a cheap preventative measure informed by science.”

Journal reference: Psychological Science, DOI: 10.1177/0956797615583071

Details of the study, including the number of people involved in it, have been changed since this article was first published.