Unique Sleep Therapy can Reduce Fear, Study

One can get rid of a phobia by a unique sleep therapy related to odors, according to a new study conducted by researchers from the Northwestern University Feinberg School of Medicine.

"It's a novel finding," said Katherina Hauner, a postdoctoral fellow in neurology at Northwestern University Feinberg School of Medicine. "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."

Hauner conducted the study in the lab of Jay Gottfried, associate professor of neurology at Feinberg and senior author of the paper. The researchers found that by sending a sensory signal related to a phobia while sleeping, could considerably decrease the fear.

The study was published Sept. 22 in the journal Nature Neuroscience.

The Experts arrived at the conclusion after studying 15 respondents. The subjects were given a mild electric shock while viewing pictures of two different faces. An odour like woody, clove, new sneaker, lemon or mint was introduced simultaneously while viewing one of the faces.

For example, 'Face 1' would always be accompanied by the odor of mint while 'Face 2' was always accompanied by lemon. As a result, both the face and odor were linked to fear.

When a subject was sleeping, one of the two odorants was frequently introduced sans the picture or the shock. Each of them slept for an average of 40 minutes. The researchers measured the phobia in two ways: through small amounts of sweat in the skin and through neuroimaging with fMRI (functional magnetic resonance imaging).. Brain scans showed changed activity in the Hippocampus (area related to memory) and the Amygdala (region associated with emotion) when the sensory signals was being sent.

"While this particular odorant was being presented during sleep, it was reactivating the memory of that face over and over again which is similar to the process of fear extinction during exposure therapy," Hauner said.

When the subjects woke up, they were asked to look at the pictures again. This time, it was observed that the level of fear had reduced.

The scientists concluded that this unique 'smell therapy' could treat major phobias in many people.

"Many people who have survived traumatic events, such as fires or road traffic accidents, have a physiological fear response to triggers of their memories. Triggers often include smells, such as smoke, petrol, antiseptic smells and alcohol. Infusing these smells during periods of slow-wave sleep could help to extinguish the fear response," Jennifer Wild, consultant clinical psychologist at the King's College London Institute of Psychiatry said to BBC.