Sleep helps process traumatic experiences: study

Geneva: Sleep during the first 24 hours after a trauma can have a positive impact on highly emotional distress and memories, according to a new study which may help develop new therapies to prevent post-traumatic stress disorder (PTSD).

Researchers from the University of Zurich in Switzerland showed a traumatic video to the subjects. The recurring memories of the images in the film that haunted the test subjects for a few days were recorded in detail in a diary. Virtually out of the blue, the test subjects would see a snapshot of what they had seen in their mind's eye, reawakening the unpleasant feelings and thoughts they had experienced during the film.

The quality of these memories resembles those of patients suffering from post-traumatic stress disorders. Other than after a traumatic event, however, they reliably disappear after a few days. Participants were randomly assigned to two groups. One slept in the lab for a night after the video while their sleep was recorded via an electroencephalograph (EEG); the other group remained awake.

"Our results reveal that people who slept after the film had fewer and less distressing recurring emotional memories than those who were awake," said Birgit Kleim from the University of Zurich. "This supports the assumption that sleep may have a protective effect in the aftermath of traumatic experiences,"
said Kleim. On one hand, sleep can help weaken emotions connected to an existing memory, such as fear caused by traumatic experiences, for instance.

On the other hand, it also helps contextualise the recollections, process them informationally and store these memories. However, this process presumably takes several nights. According to the researchers, recommendations on early
treatments and dealing with traumatised people in the early phase are few and far between.

"Our approach offers an important non-invasive alternative to the current attempts to erase traumatic memories or treat them with medication," said Kleim.
"The use of sleep might prove to be a suitable and natural early prevention strategy," he added. The study was published in the journal Sleep.