The brain processes emotional experiences during sleep, according to new research.
A study at Berkley University revealed that REM sleep has the potential to take away some of pain of difficult memories, by preventing the release of stress chemicals.
The discovery is hoped to reveal new treatment pathways for patients with post traumatic stress disorder.
Professor Mathew Walker, senior author of the study, explained: "The dream stage of sleep, based on its unique neurochemical composition, provides us with a form of overnight therapy."
In the case of patients with post traumatic stress disorder, sleep processes that ease stress may be malfunctioning.
"[Post traumatic stress patients] relive the whole visceral experience once again because the emotion has not been properly stripped away during sleep."
Sleep is essential to mental health and sleep disturbances in those who experience post traumatic stress are the most treatment-resistant symptoms.
Failing to get enough sleep often leads to drug and alcohol abuse, and suicide in patients.
In a previous study, prazosin was found to significantly reduce trauma nightmares and improve sleep quality of those who experience post traumatic stress.
Read about support and personalised care at Barchester care homes for anyone with mental health concerns.