By Nick Collins, Science Correspondent 7:30AM GMT 24 Nov 2011
Sleeping on problem really does help because dreaming provides overnight therapy for painful memories, a California University study has found.
When we enter the dream stage of sleep, known as REM, the stress systems in our brain become deactivated while our brain runs over recent emotional memories.
Brain scans showed that after sleeping, the emotional centre of the brain becomes less active while areas that govern rational thought take over, helping us to get over painful experiences from the previous day.
The study could explain why post-traumatic stress disorder victims, who typically suffer from disturbed sleep, have severe difficulty overcoming painful memories, experts said.
Although there is no scientific consensus on exactly why we spend a third of our lives sleeping, the study adds to growing evidence on the importance of the REM phase, which takes up 20 per cent of our total sleep.