B.D., a 34-year-old with a lifelong fear of spiders, found his phobia intensified after a trip to Australia where he encountered the Huntsman variety, a hairy tarantula that scuttles out from behind curtains and is notorious for entering cars and scurrying across the dashboard.
But today, after two hours of exposure therapy as part of a study at Northwestern University, B.D. finds spiders tame and amusing -- so much so that he allowed a hairy, Chilean rose tarantula named Florence to amble up his arm.
"It was like the ultimate extreme sport, a chance to face my fears in a very literal sense," B.D., an administrative assistant, wrote on a blog about his experience on his blog, "Room 101."
"It's been three years now, but I am still amazed whenever I react calmly and reasonably to their presence in my life," he wrote. "Just yesterday I helped a big green fellow off my desk, marveling that I didn't flee the room instead."
In 2009, B.D. was paid $100 to take part in a study at Northwestern University's Feinberg's School of Medicine, the first to document the immediate and long-term brain changes after exposure therapy. There, 12 terrified subjects were exposed to a variety of spiders -- first in photos, then in a terrarium and finally in the palm of their hands.
The study revealed that a single brief therapy session for adults with a lifelong fear of spiders -- or arachnophobia -- showed lasting changes to the brain's response to fear.
"Signing up for the study was one of the bravest things I've ever done, and I'm very proud," he wrote.
Arachnophobia is one of the most common specific phobias, and those who are afraid will go to great lengths to make sure they never see a spider. They may avoid hiking or camping or any situation where a spider might be present.
Specific phobias, which fall under anxiety disorders, affect about 7 percent of the population, according to the researchers. The most common include fear of blood, needles, snakes, flying and enclosed spaces.
But they say that their study may be applicable to all kinds of common phobias, as well as obsessive-compulsive disorder and post traumatic stress disorder.
"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," said lead researcher Katherina Hauner, a post-doctoral fellow in neurology.
"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. They were thrilled by what they accomplished."
The study, which was published in the journal, Proceedings of the National Academy of Sciences, was the first to use functional MRIs to measure anxiety in the brain before and after exposure to the feared object.
Not only were patients less afraid after the two-hour therapy session, but they were phobia-free six months later.
The anxiety levels in their brain were measured at different intervals. When subjects experienced fear, certain parts of the brain, like the amygdala, insula, and cingulate cortex, lit up with activity on a functional MRI scan.
When the same study participants were asked to handle the tarantula six months later, "they walked right up to it and touched it," according to Hauner.
Study participants had to meet the criteria for specific phobias as defined by the American Psychiatric Association's a Diagnostic and Statistical Manual of Mental Disorders.
"They had to be much more afraid of spiders than the average person," said Hauner. "And to meet the diagnostic criteria, it had to interfere with their life."
"Some wouldn't go home or stay in a dorm room for days if they thought a spider was there," she said. "One person avoiding traveling -- but after the study, they went on a trip."