Don’t sleep on it, you’ll just feel worse! Shut-eye can preserve painful memories
Sweet dreams Researchers say that sleeping after watching something traumatic can make us feel worse
After a hard day, we are often advised to ‘get a good night’s sleep’.
But that is probably exactly what we don’t want to do, according to scientists, who have found sleep can preserve painful memories and make us feel worse.
In tests, researchers showed that people made to watch an upsetting or traumatic event felt less emotional if they stayed awake afterwards.
The neuroscientists said it makes evolutionary sense, as our ancestors would have survived by keeping vivid memories of life-threatening situations so they could avoid them in the future.
They asked 106 men and women to look at pictures on a computer screen. Some were negative – such as violence, wars and car accidents – and others neutral. They were asked to rate their emotional response to them between one and nine.
Twelve hours later, they were again shown pictures, some new and others they had already seen, and asked whether they had seen the picture before and to rate their response again.
Half the group saw the two batches in the evening and the following morning after a sleep. The others saw them for the first time in the morning and the second time in the evening of the same day without sleeping.
Those who had slept found the pictures just as upsetting if not more so than the first time – whereas those who stayed awake found them far less so, the University of Massachusetts researchers found.
It suggests people who sleep after a traumatic event will find memories or flashbacks of it more upsetting than those who have managed to stay awake.
The researchers say it could change everything scientists have assumed about sleep – as it was previously thought to ease our minds.
Co-author Dr Rebecca Spencer said: ‘What we’ve shown is that sleep not only protects our memory but also seems to preserve the emotional response we had during that event, and that’s never been shown before.
‘It’s interesting that it is common to be sleep-deprived after witnessing a traumatic scene, almost as if your brain doesn’t want to sleep on it – and that is probably a very healthy biological response.’
Dr Spencer said the findings, published in the Journal of Neuroscience, have implications for people with post-traumatic stress disorder or giving eyewitness testimony to an accident or crime.
The team will do more tests to work out how much sleep deprivation is needed – but say they assume it is proportional to the trauma experienced.