Worry began to draw the attention of researchers about 25 years ago, when they started to finetune their understanding of the spectrum of anxiety related pathologies. In the early 1980s psychologist Thomas Borkovec of Pennsylvania State University, a pioneer in this field, became interested in the trait while investigating sleep disorders. He found that intrusive cognitive activity at bedtime— worrying—was a factor in insomnia.
By 1990 Borkovec and his colleagues developed the Penn State Worry Questionnaire, a diagnostic tool that helped researchers show excessive fretting to be a feature of all anxiety disorders, especially generalized anxiety disorder (GAD). Psychologists revised the official psychiatric guidelines (then the Diagnostic and Statistical Manual of Mental Disorders III) to reflect this understanding, calling worry the cardinal feature of GAD and making chronic worry a recognized mental health problem. It is now known to affect 2 to 3 percent of the U.S. population, according to the National Institute of Mental Health. Borkovec defined three main components of garden-variety worry: overthinking, avoidance of negative outcomes and inhibition of emotions. Mennin explains that worry piggybacks on humans’ innate tendency to think about the future: “they crave control.” He says “chronic worriers see the world as an unsafe place and want to fight this sense of unrest.”
Overworriers feel that fretting gives them this control, and they tend to avoid situations they can’t have power over. In a 1995 study Borkovec found that people agonized about matters that rarely occurred. The participants, nonetheless, often reported that they believed the overthinking about a possible negative event had prevented it from taking place. Unsurprisingly, worriers show increased activity in areas of the brain associated with executive functions, such as planning, reasoning and impulse control. In 2005 psychologist Stefan Hofmann of Boston University used an electroencephalogram (EEG) to measure activity in the prefrontal cortex, before and after 27 undergraduates were told to give a speech in public. He confirmed previous evidence that activity in the left frontal cortex increases for people who worry compared with those who do not, suggesting that the left frontal cortex plays a prominent role in worrying. Trying too hard to be in command of a given situation or their own thoughts may backfire when worriers are instead overrun with repetitive apprehensions.
Research shows that the more we dwell on negative thoughts, the more those threats feel real and the more they will repeat in our skulls, sometimes uncontrollably. In 1987 Daniel M. Wegner, a psychologist at Harvard University, found that when people were told not to think about a white bear, they tended to mention it about once a minute. In the experiment, Wegner left a participant in a room with a microphone and a bell and asked the volunteer to talk freely about any topic. At one point, he interrupted the person’s monologue and told him to continue talking— but this time, not to think of a white bear. If the subject did think of a white bear, he had to ring the bell. On average, people rang the bell more than six times in the next five minutes and even said “white bear” out loud several times. “By trying to put a worry or a thought out of our mind, it only makes the worry worse,” Wegner says. “Just like when a song gets stuck in your head, you think you ought to be able to get rid of it, but you only end up making it stick more by trying to push it away.” Two mental processes may be at play here, according to Wegner. First, by consciously looking for distractions from the white bear (or your nagging worry), you remain somewhat aware of the undesired thought. The second reason suppression fails is that often you are making an unconscious effort to catch yourself thinking of the forbidden thought, ultimately sensitizing your brain to it.
Two emotion-processing areas of the brain are also involved in worry: the anterior insula and the amygdala. A 2008 Psychological Science study that used functional MRI found that when participants anticipated losing a significant amount of money in the future, activity increased in their anterior insula. That area not only becomes more active in response to worry, but the inclination to worry is also reinforced, because people believe that the act helps them avoid potential losses. The researchers concluded that sometimes, when it comes to making daring monetary decisions, overthinking may turn out to be a good thing.
In 2009 Jack Nitschke, a clinical psychologist at the University of Wisconsin–Madison School of Medicine and Public Health, reported using fMRI to measure activity in the amygdala while GAD patients and healthy subjects viewed pictures of items that were negative (for instance, mutilated bodies) or neutral (say, a fire hydrant). A few seconds before seeing the images, patients received a cue to let them know whether to expect a negative or neutral photograph. Although GAD and healthy subjects experienced no difference in amygdala activation when shown either type of picture, GAD patients displayed unusually high levels of amygdala activity to both negative and neutral cues—suggesting that merely anticipating the possibility of something negative in the future recruits specific neural circuitry, Nitschke says.
Source of Information : Scientific American Mind November-December 2009