The study involved 66 spider-phobic women who watched a video of a spider 14 times. The participants were randomly divided into different groups to either watch the video every two hours or every 12 hours, and either in the morning or evening, or after spending a night sleeping or a full day awake.
The researchers also sounded off a loud noise during some of the videos and then measured the participants’ palm sweat in response.
Overall, women who managed to get a good night’s sleep after watching the spider videos — before being shown the spiders again — were less likely to rate the spider high on a scale of “fearfulness, disgust, and unpleasantness,” according to the Harvard Gazette.
On the other hand, subjects who stayed awake for 12 hours after watching the spider videos and were then shown the videos again at the end of the day exhibited a stronger stress response.
There was no evident difference in reaction between participants who viewed the spider videos in the morning or the evening.
“Thus, sleep following exposure therapy may promote retention and generalization of extinction learning,” the researchers wrote in the study.
The researchers added that REM sleep in particular could be responsible for the effect.
Recently, a Proceedings of the National Academy of Sciences study showed that severely arachnophobic adults who participated in just one session of therapy experienced brain changes that allowed them to hold a tarantula in their hands. The effect lasted six months after the therapy session.
“Before treatment, some of these participants wouldn’t walk on grass for fear of spiders or would stay out of their home or dorm room for days if they thought a spider was present,” study researcher Katherina Hauner, Ph.D., postdoctoral fellow in neurology at Northwestern University Feinberg School of Medicine, said in a statement.
“But after a two or three-hour treatment, they were able to walk right up and touch or hold a tarantula. And they could still touch it after six months,” Hauner said.
The study is published in the Journal of Psychiatric Research.
Source: Journal of Psychiatric Research