Reactivating the emotional memories of participants prior to them playing a computer game reduced occurrence of related unwanted memories in the following week.
It is estimated that around 7-8% of the US population will experience post-traumatic stress disorder (PTSD) at some point in their lives, with women more likely to develop the condition than men.
PTSD is triggered by exposure to a traumatic event. Symptoms include feeling tense, sleep problems, feelings of guilt or depression and frightening thoughts. One of the most common symptoms is repeated visual memories of the event that triggered the disorder.
People with PTSD often remember moments of their terrifying ordeal in vivid detail and feel as if they are reliving the event over and over, which can severely impact day-to-day life.
Psychotherapy is one of the primary treatments for PTSD. This may include cognitive restructuring, which involves helping people make sense of their bad memories in an attempt to help them cope. But according to the study researchers, strategies to prevent such memories are limited.
"Currently, there are recommended treatments for PTSD once it has become established, that is, at least 1 month after the traumatic event, but we lack preventative treatments that can be given earlier," explains senior study author Emily Holmes, of the Medical Research Council Cognition and Brain Sciences Unit in the UK.
Past studies have indicated that people who played the computer game Tetris within 4 hours of watching video footage of traumatic events were less likely to have fewer unwanted memories of those events.
However, Holmes and colleagues note that it is unrealistic to expect people who are involved in a traumatic event to play a computer game in the 4 hours following. But could doing so within 24 hours help reduce occurrence of unwanted memories?
Combination of memory reactivation and Tetris reduced intrusive memories
To test whether this might be the case, the researchers conducted two experiments that investigated the theory of memory reconsolidation - the idea that long-term memories can be recalled and modified.
The idea was to reactivate old emotional memories of participants and see whether the reoccurrence of these memories could be reduced by computer game play.
In the first experiment, the researchers induced intrusive memories in 52 participants by showing them a 12-minute film of traumatic events, such as a man drowning at sea or a young girl being hit by a car.
Twenty-four hours after watching the film, half of the participants were shown stills from it as a way of reactivating their memories. They then took part in a 10-minute filler task - allowing time for memory reconsolidation to begin - followed by 12 minutes of playing Tetris. The other half of the participants acted as controls, only taking part in the filler task before sitting quietly for 12 minutes.
Over the next week, all participants were required to keep a diary of any intrusive memories that occurred - defined as "scenes of the film that appeared spontaneously and unbidden in their mind."
The team's findings - published in the journal Psychological Science - revealed that the participants whose memories were reactivated before playing Tetris experienced fewer intrusive memories from the film than the control group.
This finding was confirmed in the second experiment, in which four groups of participants performed the same tasks. In this experiment, however, the team also tested whether memory reactivation alone or Tetris alone could reduce occurrence of intrusive memories.
They found it was only the use of memory reactivation and Tetris combined that led to fewer intrusive memories.
Commenting on their results, study co-author Ella James, also of the Medical Research Council Cognition and Brain Sciences Unit, says:
"Our findings suggest that, although people may wish to forget traumatic memories, they may benefit from bringing them back to mind, at least under certain conditions - those which render them less intrusive."
Holmes notes that their research is in its early stages and further studies are required, but she says they hope to develop their approach, with the aim of creating a potential strategy to reduce intrusive memories for people with PTSD and other trauma-related conditions.
"Better treatments are much needed in mental health," she adds. "We believe the time is ripe to use basic science about mechanisms - such as research on memory reconsolidation - to inform the development of improved and innovative psychological treatment techniques."
In August 2014, Medical News Today reported on a study suggesting the way a person's memory is processed may influence their risk of developing PTSD.
Published in the journal Clinical Psychological Science, the study suggests people who recall higher numbers of external details related to the traumatic event - such as editorial statements - may be at higher risk for PTSD.