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.
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.