A dream-shaping mobile phone app can help ensure a restful night, research has shown – and the best time to use it might be when there is a full moon.

The free iPhone app, launched in 2012, monitors sleep patterns and plays carefully-constructed sounds designed to evoke pleasant dreams.

Results of a new mass-participation experiment show that the Dream:On download really does influence dreaming, helping people to sleep peacefully and wake up happy and refreshed.

One unexpected finding was that a full moon appeared to bring on bizarre dreams in study participants.

A possible reason is that moonlight streaming through the bedroom curtains creates feelings of unease inherited from our prehistoric past, when predators were a constant threat.

Psychologist Richard Wiseman, from the University of Hertfordshire, said: “People fall asleep later when there’s a full moon, sleep about 20 minutes less, and spend less time in deep sleep. We know that poor sleep is associated with disturbing dreams.”

For the two-year dream control study, Wiseman’s team collected millions of dream reports from volunteers who downloaded the app more than 500,000 times.

The app works by using a motion detector to sense when a sleeper is dreaming and then playing a chosen ‘soundscape’ that conjures up thoughts of a particular scene – for instance, a forest or the seaside.

“If someone chose the nature landscape then they were more likely to dream about greenery and flowers,” said Wiseman. “In contrast, if they selected the beach soundscape then they were more likely to dream about the sun beating down on their skin.

People fall asleep later when there’s a full moon, sleep about 20 minutes less, and spend less time in deep sleep

“Having positive dreams helps people wake up in a good mood, and boosts their productivity. We have now discovered a way of giving people sweet dreams, and this may also form the basis for a new type of therapy to help those suffering from certain psychological problems, such as depression.”

People who are depressed dream about five times more than average, he said.

“One of the most effective ways of curing depression is to stop depressive dreaming, but you can’t maintain that kind of therapy,” Prof. Wiseman added.

“It’s possible we might be able to do stuff during the night that’s useful during the day.”

The full moon’s link with dreams was also detected last year by neuroscientists at the University of Basel in Switzerland. They too found that people’s dreams were especially strange around the time of the full moon.

“That’s something we weren’t looking for – it’s completely bizarre,” said Wiseman.

The Swiss scientists theorised that sleep was disturbed by the full moon because of our evolutionary past. The idea is that it summons up old fears of being ill-met by moonlight in an environment where we had to hide from predators.

Wiseman pointed out that melatonin, the hormone that regulates the sleep-wake cycle, is highly sensitive to light.

He was not convinced by the evolutionary theory but accepted that the effect was “probably psychological”.

“It’s one of those cases where you say let the data speak for itself,” he said.

He describes the findings in more detail in his book Night School published by Pan Macmillan.