Imaging Study Shows How 'Exposure Therapy' Changes Brain
By Salynn Boyles
WebMD Health News
Reviewed by Louise Chang, MD
May 21, 2012 -- Before receiving treatment for her lifelong fear of spiders, one Chicago college student would flee her dorm for days if she merely suspected one's presence. She worried that her phobia would keep her from living on her own after graduation.
Another woman did not travel because she was terrified of spiders, even though she had long dreamed of going to Europe.
But after a single, two-hour therapy session in which they confronted their fear in the form of a tarantula named Florence, both women showed remarkable improvement in their actions -- and in their brains -- according to a new imaging study.
The therapy was so successful that people who previously could not be in the same room with the tarantula were able to touch and even hold the spider immediately after the session -- and they still showed little fear of Florence when reunited with her six months later.
Confronting Phobias Head On
About 1 in 10 Americans have phobias -- excessive fears of an object or situation that can have a profound impact on life.
Arachnophobia, or the fear of spiders, is among the most common, along with fear of snakes (ophidiophobia), heights (acrophobia), needles (trypanophobia), flying (pteromerhanophobia), and enclosed spaces (claustrophobia).
Exposure therapy, which involves planned confrontation with the feared object, is among the most successful treatments for phobias and other anxiety disorders, such as social anxiety disorder and obsessive-compulsive disorder (OCD).
The treatment is thought to train the brain to stop sending unwelcome "fight or flight" fear signals, and a new brain imaging study from Chicago's Northwestern University Feinberg School of Medicine suggests that this is exactly what happens.
Brain Imaging Reveals Key Changes
Before the single two-hour exposure therapy session, the 12 study participants were afraid to even look at pictures of spiders.
When they did, brain scanning showed that regions of the brain most closely associated with fear response lit up with activity.
Immediately after the therapy session, the regions were much less active in response to the pictures, and they remained less active six months later.
Key brain areas associated with inhibiting fear were very active immediately after the therapy. They were much less active six months later, even though the study participants were still free of their spider phobia, researcher Katherina K. Hauner, PhD, tells WebMD.
"It appears their brains had reorganized in some way to maintain the improvement," she says.
The researchers were also able to predict long-term responses based on brain activity immediately after treatment.
Two Hours With a Tarantula
The goal of the two-hour session was to get the study participants to approach and then touch the tarantula, which was housed in a closed terrarium.
Hauner says most of the participants could not get closer than 10 feet from the terrarium at the beginning of the session.
"The first thing we did was tell them about spiders, specifically how fragile they are and how they are more likely to try and hide from you than attack you," she says. "The next step was getting [the participants] to gradually approach the spider while maintaining their focus on it."
At the beginning of the session, the participants typically showed classic signs of extreme anxiety, such as agitation, sweating, and racing heart.
But by the end, most were able to approach the caged spider and even touch and hold it without fear.
"They understood that the spider's movements were predictable and could be controlled," Hauner says. "Fear is about not having control and not being able to predict what will happen."
Exposure Therapy Changed Lives
Six months later, many participants told Hauner the single-session therapy had changed their lives for the better.
The woman who was previously afraid to travel was planning her European dream vacation, and the college student called the therapy the most amazing thing she had ever done.
One male participant even planned to get a spider tattoo to celebrate overcoming his phobia.
Exposure therapist Paula Young, PhD, says most people with phobias spend their lives trying to avoid the object of their terror.
Young directs the Family Institute Depression Treatment Program at Northwestern, but she was not involved in the study.
"It is natural for people to avoid what they are afraid of," she says. "But if you do that you never get the opportunity to find out that the thing you are afraid of isn't really that scary. And you don't find out that the anxiety you feel will eventually resolve on its own if you don't try to escape."
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