The Mind and the Brain by Jeffrey M. Schwartz, Sharon Begley

is locked so often as to render them unable to hold a job, even though part of their brain knows full well that it is securely locked. They count the steps from their car to the door of the office where they have a job interview, hoping and praying that the number will turn out to be a perfect square, a prime, a member of the Fibonacci sequence, or something else magical, since if it is not, they must do an about-face and return to the car to try again. They do this time and again, knowing that the interview time is fast approaching and that—oh, God, they’ve lost out on another job because of this crazy disease. OCD has a lifetime prevalence of 2 to 3 percent; in round numbers, it affects an estimated one person in forty, or more than 6 million Americans, typically striking in adolescence or early adulthood and showing no marked preference for males or females.
    Excessive and ritualized hand-washing may be the best known of the OCD compulsions, but there are scores of others. They include alphabetizing the contents of a pantry, repeatedly checking to see whether a door is locked or an appliance is turned off, checking over and over to see whether you have harmed someone (peeking in on a sleeping child every minute, for instance), following rituals to ward off evil (like scrupulously avoiding sidewalk cracks), touching or tapping certain objects continuously, being unable to resist counting (totting up, every day, the traffic lights you pass en route home), or even excessively making lists. OCD can manifest itself as obsessions about order or symmetry, as expressed in an irresistible need to line up the silverware just so, or as an obsession about hoarding, as expressed in never throwing out old magazines and newspapers. Paradoxically, perhaps, giving in to the urge to wash or check or count or sort, which the patient does in the vain hope of making the dreadful feeling recede, backfires. An OCD compulsion does not dissipate like a scratched itch. Instead, giving in to the urge exacerbates the sense that something is wrong. It’s like chronic poison ivy of the mind: the more you scratch it, the worse it gets.
    Someone with obsessive-compulsive disorder derives no joy from the actions she takes. This puts OCD in marked contrast to, for instance, compulsive gambling or compulsive shopping. Although both compulsive shoppers and compulsive gamblers lack the impulse control to resist another trip to the mall or another game of video poker, at least they find the irresistible activity, well, kind of fun. An OCD patient, in contrast, dreads the arrival of the obsessive thought and is ashamed and embarrassed by the compulsive behavior. She carries out behaviors whose grip she is desperate to escape, either because she hopes that doing so will prevent some imagined horror, or because resisting the impulse leaves her mind unbearably ridden with anxiety and tortured by insistent, intrusive urges. Since the obsessions cannot be silenced, the compulsions cannot be resisted. The sufferer feels like a marionette at the end of a string, manipulated and jerked around by a cruel puppeteer—her own brain.
    Freud believed that OCD is a manifestation of deep emotional conflicts. As a result, patients who sought traditional psychiatric therapy for the illness were typically told that the rituals they performed or the thoughts they could not silence were rooted in sexual conflict and reflected, for instance, a repressed memory of childhood trauma. The content of the disease—why one patient can’t stop thinking that she left the coffee maker on, while another is beset by a compulsion to wash doorknobs—may indeed reflect the individual’s personal history. But as yet there is no biological explanation for why OCD expresses itself one way in one patient and a different way in another. Nor is it clear what the ultimate cause of obsessive-compulsive disorder is, though there is clearly a genetic contribution.
    Until the mid-1960s, the