In short
- What was done. Within six hours of a road accident, patients briefly recalled the worst moments and then played about twenty minutes of Tetris. The comparison group wrote an activity log for the same time.
- Why a game. A memory stays modifiable for some hours after it forms. Tetris makes heavy demands on the same visuospatial system the trauma image uses, so the two compete.
- The result. Fewer intrusive memories over the following week, and they faded faster.
- The limits. No difference on other symptom clusters, and none at one month. The authors call it a proof of concept.
- What it is not. Not a treatment for post-traumatic stress disorder, which responds to trauma-focused psychological therapy.
An Odd Prescription
A video game, in an emergency department
Some years ago, patients arriving at a hospital emergency department after a road traffic accident were offered something unusual. Within six hours of the crash, before they went home, they were asked to think briefly about the worst moments of what had happened, and then to play about twenty minutes of Tetris on a handheld console.
This was not a distraction exercise and it was not anybody’s idea of a joke. It was a randomised controlled trial, designed on a specific theory about how memory works, and it was published in Molecular Psychiatry.
Why a Video Game
Memory is soft for a few hours
The intrusive memories that follow a frightening event are largely sensory, and largely visual. People do not usually re-experience a crash as a narrative. They get an image: the windscreen, the headlights, a particular angle of the road, arriving unbidden and out of sequence.
Two well-established ideas were combined. The first is that a memory is not fixed at the moment it is formed. There is a window of some hours during which it is still being consolidated and is therefore still modifiable. The second is that visuospatial working memory has a limited capacity: two demanding visual-spatial tasks running at once will interfere with each other.
If a trauma memory is still being laid down, and you occupy the same visual machinery with something else demanding, the sensory trace should be laid down less strongly.
Tetris is close to ideal for this. It is intensely visuospatial, it requires continuous mental rotation, it is absorbing without being verbal, and almost anyone can play it on a small screen while sitting in a hospital corridor.
What the Trial Did
Reminder, then twenty minutes of falling blocks
Patients who had come to the emergency department after a motor vehicle accident were randomly assigned to one of two conditions, both delivered within six hours of the accident. The intervention group received a brief reminder cue for the trauma memory followed by roughly twenty minutes of Tetris, with instructions to use mental rotation while playing. The control group spent the same amount of time writing an activity log, an attention-matched task with no visuospatial demand.
Both groups then kept a daily diary of intrusive memories of the accident for the following week. The number of intrusive memories was the outcome the study was designed to measure.
What It Showed, and What It Did Not
A real effect, and honest limits
The Tetris group had fewer intrusive memories over the week than the control group, and their intrusions dropped away faster. A separate clinical measure of intrusion symptoms at one week agreed. Patients found the task easy, helpful and not particularly distressing, which for an intervention delivered hours after a crash is not a trivial finding.
The limits should be stated as plainly as the result. The difference did not hold on other symptom clusters, and it did not persist at one month. The study was explicitly a proof of concept, small, and designed to justify a bigger trial rather than to change practice. A later pilot trial and a growing set of related studies have broadly supported the mechanism, but this is an active research programme, not a settled treatment.
One clarification worth making, because the words are almost identical. An intrusive memory is a replay of something that actually happened to you. An intrusive thought, the kind seen in OCD, is an unwanted idea about something that has not happened and that you do not want to happen. They feel similar and are treated completely differently. The guide to intrusive thoughts and OCD covers the second kind.
Why the Idea Matters Anyway
Prevention, which psychiatry rarely gets to do
Almost everything psychiatry offers arrives after a disorder has established itself. An intervention delivered in the first hours, that costs almost nothing, requires no specialist, carries no drug side effects and might reduce how strongly a traumatic memory sets, would be an unusual kind of tool. Emergency departments are already full of people in exactly that window.
There is a pleasing footnote. The phrase Tetris effect existed long before any of this, describing the way heavy players see falling blocks when they close their eyes. A study published in 2000 found that people with severe amnesia, who could not remember playing the game at all, still reported the falling-block images as they fell asleep. The game was leaving a trace in a memory system that was otherwise not working. It took another seventeen years for someone to ask whether that same reach into visual memory could be pointed at something useful.
If images from something keep coming back
Intrusive memories in the days after a frightening event are common and usually settle on their own. When they persist for weeks, disturb sleep, or make you avoid places and situations you used to manage, that is worth assessing rather than waiting out. Post-traumatic stress responds to treatment, and treatment works better the less it is delayed.
Dr. Shaurya Garg, MD Psychiatry (AIIMS New Delhi), offers structured psychiatric assessment, with fees listed transparently. Consultations are available online across India and in person in New Delhi, and every consultation is private.
Sources and further reading
· Stickgold R. et al. Replaying the game: hypnagogic images in normals and amnesics. Science, 2000
· NICE guideline NG116: Post-traumatic stress disorder
These sources are provided for education. They do not replace individual clinical assessment.
Common questions
Does playing Tetris prevent PTSD?
That is not what the research shows. The trials measured the number of intrusive memories in the week after a trauma, and found fewer in the Tetris group. They were not designed or powered to show prevention of PTSD as a diagnosis, and the difference did not persist at one month.
Why Tetris specifically?
Because it makes heavy demands on visuospatial working memory, requires continuous mental rotation, is absorbing without being verbal, and can be played on a small screen by almost anyone. The theory predicts that any task with those properties should compete with the visual elements of a memory that is still consolidating.
How soon does it have to be played?
In the emergency department trial the intervention was delivered within six hours of the accident, during the window in which the memory is thought to still be consolidating. Later applications, aimed at memories that are reactivated and briefly become modifiable again, are a separate and newer line of research.
Should I play Tetris after something frightening happens?
It is unlikely to do any harm, but it should not replace anything. Most intrusive memories in the first days after a frightening event settle by themselves. If they persist for weeks, disturb sleep, or lead you to avoid places and situations, that needs proper assessment rather than a game.
Is this an accepted treatment?
No. It is a promising and well-conducted line of research, described by its own authors as proof of concept. Established treatments for post-traumatic stress disorder are trauma-focused psychological therapies, with medication in some circumstances.