First, it was shown that it's possible for us to learn new information as we sleep. And now, a new study shows it's also possible to conquer our fears as we snooze.
The study, published in the journal Nature Neuroscience, suggests that nighttime treatment of phobias could be a good addition to daytime phobia treatments of exposure therapy.
"It's a novel finding," study researcher Katherina Hauner, who is a postdoctoral fellow in neurology at Northwestern University Feinberg School of Medicine, said in a statement. "We showed a small but significant decrease in fear. If it can be extended to pre-existing fear, the bigger picture is that, perhaps, the treatment of phobias can be enhanced during sleep."
The idea for the study builds off the knowledge that sleep is vital to the strengthening of new memories and that memory consolidation occurs during the slow-wave (deep) sleep.
Hauner and colleagues conducted their study on 15 healthy people, who were mildly shocked in response to seeing two faces, while simultaneous being exposed to one of several specific smells -- including new sneaker, mint, lemon, wood and clove -- while seeing each face. The researchers did this with the purpose of having the study participants associate the smell and the face with fear (being shocked).
Then, as the study participants were sleeping, researchers exposed them to just one of the two scents linked with the fear response. They exposed them to the scents when the participants were in slow-wave sleep; however, this time, the scents were not accompanied with the mild electrical shock.
When the participants woke up, researchers again showed them the images of the faces and tested their fear responses to them. They found that when the image of a face was shown that was associated with a scent smelled during sleep, the fear response by the study participant was lower, compared with the face shown that was associated with a scent not exposed to them during sleep.