Does dreaming soothe painful memories?

The act of dreaming can serve to reduce painful memories, new research has suggested. Investigators from the University of California, Berkeley, found that during REM sleep - also known as the dream phase - a person's stress chemistry comes to a halt and the brain serves to take the edge off burdensome recollections.

Published in the journal Current Biology, the study could offer clues as to why people dream, while explaining why people with post-traumatic stress disorders find it hard to recover from difficult experiences and often suffer reoccurring nightmares.

Matthew Walker, Associate Professor of Psychology and Neuroscience at the learning institute - which was founded in 1868 in the wake of the US gold rush - said: "The dream stage of sleep, based on its unique neurochemical composition, provides us with a form of overnight therapy."

He likened this type of snoozing to a "soothing balm" that counters the negative experiences of the day before.

Dr Jacob Empson of the University of Hull commented: "I'm not sure that Professor Walker has proved that the function of dreaming sleep is a psycho-therapeutic one, when repeated nightmares in people suffering from PTSD do not improve their symptoms.

"A good night's sleep does of course make one feel more composed and it is perhaps this effect of sleep which is responsible for his interesting results."

Professor Colin Espie will be giving a free public lecture in Birmingham on Wednesday 30 November under the title Wake Up to Sleep.