Dan from Detroit is a checker. Stubbly and weary, he sits in a hallway lounge area wearing an Adidas T-shirt and track pants and fiddling with a pack of Marlboros and a cup of black coffee. At 36, Dan admits to having squandered hours of his life. He has a fear of stepping on electrical cords and causing an accident, and will often worry about tripping on cords that aren’t even there. “I have a fear that I’m gonna pass a counterfeit bill and get in trouble,” he says. “I check money before I go to the store.” He’ll hold a 20 up to a lightbulb and flip it over again and again. He’s afraid he’ll start a fire with a tossed cigarette butt, so he’ll stare at a stubbed-out smoke for several minutes to make sure there’s no red ash. Perhaps it’s no surprise that Dan has resorted to marathon binges of self-medication. “I had a really serious drinking problem, but that’s behind me,” he says. “When I did drink, the OCD went away about 99 percent. I would go on binges for three to five days. When I ran out, I was so desperate to get more. If I’d kept it up I probably would’ve landed in prison.”

It’s that threat of prisons both mental and concrete that explains why many of these folks are willing to devote a summer night to Jonathan Grayson’s adventures in Dumpster-petting and dollar-shredding. Even though his virtual camping trip amounts to a crash course in exposure therapy (“We’re not really doing treatment there, we’re kind of doing a demonstration,” the doctor says), Grayson is quick to point out that “we do have people who will have a permanent gain from that. It’s like those things where people walk on hot coals. For some people even having the experience of that is eye-opening.”

Real exposure therapy can turn into a lifelong practice. First a patient goes through an intensive program of treatment, which usually lasts a few weeks or months, and then, if he’s following orders, he’ll continue with a daily dose of exposures on his own, sort of like a psychological trip to the gym. This can get bizarre—you’ll hear about sufferers who set aside an hour every day to smear their hands with gunk from dirty dishes—but it pays off, Grayson says. “There will be times when they are symptom-free,” the doctor says. “They really won’t be thinking about it at all.” OCD sufferers are prone, like addicts, to relapse, but evidence suggests that that initial taste of freedom can go a long way toward breaking them out of the brain rut.

As the coup de grâce in Texas, the doctor leads a posse of men into a restroom. He kneels next to a urinal. One after another, the men place their fingertips on the porcelain lip of the pissoir—the very spot where one’s urine tends to dribble. Then Grayson places a white Tic Tac in their hands, and they pop the mint into their mouths. (One of the most fearless guys skips the mint altogether—he taps the urinal and then licks his fingers with his tongue.) “I didn’t like that,” says Mike, a 36-year-old sufferer from Houston. Sweat is beading on his brow. “I don’t like that kind of contamination.” He’s not supposed to. The point is to get comfortable with discomfort; with OCD, the only real cure is to care just a little bit less. “For some of you,” Grayson tells them when they’ve made it through the ceremony of the urinal, “tonight might be the beginning of a miracle.”