University researchers in Switzerland and the US have stated that bad dreams possibly hold a positive benefit, as they allow the brain to control fear better during the hours the person is awake.

The researchers examined how the human brain responds to different types of dreams and found that when the brain experiences a bad dream it was more effective at reacting to ‘frightening experiences’ during the waking hours. However, extreme nightmares didn’t provide this benefit, and instead had much more of a negative impact on the person.

The purpose of their study was to determine whether bad dreams, which were classed as ‘moderately frightening’ may have a useful benefit to the person when they are awake afterwards. They analysed how the emotions experienced during bad dreams connected to emotions and feelings during the waking hours. They discovered that bad dreams did in fact help people to react better during experiences that could be classed as frightening and these findings were published in Human Brain Mapping.

After waking from a bad dream, the area of the persons brain which controls the response to fear was found to be working more effectively. The research suggested that dreams which may be unpleasant and scary, have a way of preparing the person for fear they may encounter when awake.

Lampros Perogamvros, a researcher in the Sleep and Cognition Laboratory at the University of Geneva said, “We were particularly interested in fear. What areas of our brain are activated when we’re having bad dreams? […] Dreams may be considered as a real training for our future reactions and may potentially prepare us to face real life dangers.”

They discovered a strong link between emotions that were felt in sleep and wakefulness, with bad dreams acting as a rehearsal for experiencing such situations in waking life. However, the benefits only lasted for dreams which were considered moderately frightening, once a dream passed a certain fear barrier and was classed as more of a true nightmare, the benefits were in fact reversed.

Mr Perogamvros said, “If a certain threshold of fear is exceeded in a dream, it loses its beneficial role as an emotional regulator.”

So, whilst slightly scary dreams may have a positive effect on how we deal with frightening situations in real life, it looks like those nightmares still really are nightmares!