After a traumatic experience, victims and witnesses often struggle with intrusive memories. These powerful, painful images from the event pop into victims’ heads seemingly out of nowhere. This symptom may last for years after the inciting incident. For many, this is the most distressing part of post-traumatic stress disorder (PTSD).

Scientists believe that memories form during the first few hours after any experience. During this period, the brain works to consolidate the information it received from our senses into something it can recall later. Importantly, many cognitive scientists believe that this process can be interrupted by introducing competing attention-grabbing visuals. Like Tetris.

Tetris, like most video games, makes players concentrate on a screen and pay attention to fast-moving elements. As each block falls from the top of the screen, we must hurry to identify where it can fit and how we can maneuver it there.

Researchers in 2009 showed 40 participants a 12-minute film featuring severe injuries and death to safely simulate a traumatic experience. After 30 minutes of waiting, half of the participants played Tetris for 10 minutes. The other half did nothing for those 10 minutes. All participants spent the next week noting every time they experienced an intrusive memory of the film. At the end of the week, the researchers tabulated how many each group experienced.

The results were remarkable. In the week after watching the film, those who played Tetris experienced less than half the intrusive memories as the group who did not.

Although the groups differed significantly in how often they experienced intrusive memories, voluntary memory of the film remained intact. That is, both groups could accurately answer questions about the movie at the end of the week. This is critical because survivors sometimes need to be able to recall details of traumatic events, for example to discuss it with a therapist or to testify in court.

Follow-up studies by different authors have validated these results, including some which involved survivors of real trauma. They did so using similar methodology, but for longer periods of time and with people who were in the hospital following a serious traffic accident or with health care workers during the COVID-19 pandemic. Most of these studies show similar results; playing a visually stimulating, attention-grabbing video game after a traumatic experience significantly reduced intrusive memories up to six months later.

Despite these follow-up studies, some key questions still remain:

• Would other video games work similarly?

• Would other visual media be effective? What about solving a puzzle, watching a movie, drawing, or looking at a Where’s Waldo book?

• What would have happened if participants had played Tetris at different times? Would it have been effective if they had played the day after the experience? After a week?

• What is it about Tetris that might have caused this effect? Was it requiring visual attention as researchers suggested, or is there another variable at play?

• Was there unintentional bias introduced by the researchers? These studies were not double-blind, meaning that the researchers knew which participants were in which condition. This could be accounted for, for example, by having all participants follow instructions in a sealed envelope.

• Do the results persist for long periods of time? I am not aware of any studies which followed up with participants after more than six months.

Despite these results, some have criticized the studies. They point out that the results included significant outliers; that researchers have not studied trauma resulting from violence which happens repeatedly (such as domestic violence); and that most studies only tested for intrusive memories and not other symptoms of PTSD. Some, but not all of these concerns have been addressed by follow-up studies. The COVID-19 study, for example, included people who experienced repeated traumatic experiences and tested for other symptoms of PTSD.

Importantly, these studies do not say that playing Tetris can reduce existing symptoms of PTSD. At best, a video game can be a distraction from feelings of distress once symptoms have begun. This research only suggests that playing a video game like Tetris can reduce future symptoms if done within a few hours of the event.

More study needs to be conducted before recommending this to the public, but the results are promising. If future studies confirm these results, we might already have an inexpensive, widely available “vaccine” for PTSD. It might soon be best practice for doctors to recommend their patients play games on their phone in the hospital.