The adage "don't go to bed angry" may have been proven true by a new sleep study.
Researchers have found that a person's emotional response after a traumatic event is improved if that person stays awake afterwards.
A study, carried out by researchers at the University of Massachusetts, found that the act of sleeping both retains and exacerbates a negative emotion.
Neuroscientists believe that the study, published in the Journal of Neuroscience, could have a significant impact on the treatment of people with post-traumatic stress disorder or witnesses testifying to an accident or crime.
"We found that if you see something disturbing, let's say an accident scene, and then you have a flashback or you're asked to look at a picture of the same scene later, your emotional response is greatly reduced if you stayed awake after the original event," said Rebecca Spencer, a neuroscientist and co-author of the study.
"It is common to be sleep-deprived after witnessing a traumatic scene, almost as if your brain doesn't want to sleep on it," she added.
A group of 68 female and 38 male young adults, who ranged in age from 18 to 30, took part in the study, in which they were asked to rate their emotional responses to a series of images. This was carried out in two phases, before and after sleep, and a polysomnograph was attached to participants' scalps, with electrodes to investigate brain processes and periods of rapid-eye movement.
Spencer plan to follow up the study with one on the link between sleep and memory in the context of ageing.