Even the most stable brain operates just a millimeter from madness. In such a finely tuned cognitive engine, only a small part must start to sputter before the whole machine comes crashing down. When that happens, reason and function come undone, rarely as dramatically as in the neurochemical storm that is obsessive-compulsive disorder

Say you leave work at 6 p.m. for what should be a 12-minute drive home. Say just as you're pulling onto the street, a child on a bicycle crosses in front of you. A few feet later, you feel the thump of a pothole. But what if it wasn't a pothole? Suppose you hit the child. You look in your rearview mirror, and all is clear, but can you be sure? So you circle back around the block. Still clear--except for a lumpy bag of leaves on the curb. But is it a bag or a child? So you circle once more. Four hours later, you finally arrive home, mutter something to your spouse about a late meeting and go to bed spent and ashamed. Tomorrow you'll do it all over again.



Devoting an entire evening to a 12-minute drive is not the only way to know you've got obsessive-compulsive disorder (OCD). You know it when you shrink from the sight of a kitchen knife, worried that you'll inexplicably snatch it up and hurt yourself or a family member. You know it when leaving the house consumes hours of your day because the pillows on your bed must be placed just right. You know it when you can't leave the house at all for fear of a vast and vague contamination that you can't even name.



We all think we know what OCD is, and most of the time we're all wrong. It's the nervous guy from Monk; it's cranky Jack Nicholson in As Good As It Gets. In the end, though, things usually work out for them. They even get the girl, who sees them as a kind of adorable emotional fixer-upper.



But OCD isn't adorable. About 7 million adults, teens and children in the U.S. are now thought to have it in one form or another, and their pain is far worse than you probably know. What's more, since one family member disabled by the disorder can destabilize an entire household, a single diagnosed case can mean several collateral victims. Worse, OCD is a condition that often masquerades as other things. It is routinely labeled depression, bipolar disorder, attention-deficit/hyperactivity disorder (ADHD), autism, even schizophrenia. Victims often conceal their problem for years, ensuring that no diagnosis--right or wrong--can begin to be made.



With the twin obstacles of secrecy and mislabeling, the average lag time between the onset of the disorder and a proper diagnosis is now a shocking nine years, according to surveys of doctors conducted by the Obsessive Compulsive Foundation, a 21-year-old organization with headquarters in New Haven, Conn. It takes an average of eight additional years before effective treatment is prescribed. If the disorder strikes a young person, as it often does, that can mean an entire childhood lost to illness. "OCD has had a slow research start," says Gerald Nestadt, co-director of the OCD clinic at Johns Hopkins University. "It's behind schizophrenia, bipolar disorder, autism and ADHD."



But all that is changing. A burst of new genetics studies is turning up insights into the causes of the disorder. Scanning technologies are pinpointing the parts of the brain that trigger the symptoms. New treatments are being developed. And refinements of old treatments, like talk and behavioral therapy, are proving more effective than ever.



"Everyone has intrusive thoughts, but most people consider them meaningless and can move on with their lives," says psychologist Sabine Wilhelm, associate professor at the Harvard Medical School and director of the OCD clinic at Massachusetts General Hospital. "For people with OCD, the thoughts become their lives. We can give those lives back to them."



THE ROOTS OF OBSESSION



ON THE WHOLE, A LITTLE ANXIETY IS A VERY good thing. It was not enough for humans in the state of nature to know there was no lion near the family cave; they also had to be able to imagine all the other places a lion could lurk. The same is true for other eccentricities of human behavior. Our anxiety about all the ways harm may befall someone else keeps us mindful of the safety of family and community. "There's a creative, what-if quality to this thinking," says clinical psychologist Jonathan Grayson of the Anxiety and Agoraphobia Treatment Center in Bala Cynwyd, Pa. "It's evolutionarily valuable."



Something woven so tightly into the genome is not likely to be shaken loose by a few thousand years of modern living. But that doesn't mean every person with eccentric traits--the woman in the office next to yours who keeps her desk impeccably neat and gets edgy if something is moved out of place, for example--has OCD. "Having these OCD-like traits is a universal experience," says Judith Rapoport, author of the landmark book The Boy Who Couldn't Stop Washing and chief of child psychiatry at the National Institute of Mental Health. "I sometimes count on my fingers when I have nothing to count." The key to diagnosing whether such behavior is authentic OCD is how great an impact the behavior has on your life. "You have to show longstanding interference with function, and that eliminates most people," Rapoport explains.



What causes some people to suffer that interference and most not? Why does their internal alarm keep shouting "Lion!" long after they've checked every place a lion could plausibly be? The answer has always been thought to lie principally in a small, almond-shaped structure in the brain called the amygdala--the place where danger is processed and evaluated. It stands to reason that if this risk center is overactive, it would keep on alerting you to peril even after you've attended to the problem.



As it turns out, the amygdala is indeed a big player in the pathological process of OCD but only one of several players. Functional magnetic resonance imaging (fMRI) and other scanning technologies have allowed researchers to peer deeper than ever into the OCD-tossed brain. In addition to the amygdala, there are three other anatomical hot spots involved in the disorder: the orbital frontal cortex, the caudate nucleus and the thalamus--the first two seated high in the brain, the third lying deeper within.



"Those areas are linked along a circuit," says Dr. Sanjaya Saxena, director of the OCD program at the University of California at San Diego. It's the job of that wiring to regulate your response to the stimuli around you, including how anxious you are in the face of threatening or frustrating things. "That circuit," says Saxena, "is abnormally active in people with OCD."

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