Public Release: 

Brain-Activity Data Clarify Contradictions In Earlier Anxiety Research

University of Illinois at Urbana-Champaign

CHAMPAIGN, Ill. -- Psychologists need not worry about years of confusing research regarding anxiety. With emotional response broken into two aspects -- worry and panic -- a distinct pattern of activity arises in the brain, researchers say.

The new findings, reported by University of Illinois researchers, show that panic attacks, or excessive psychophysiological arousal, are reflected in people who worry by increased electrical activity in the right posterior of the brain during times of environmental stress. While at rest, worriers in the study showed more activity in the left frontal section of the brain.

As a result of the findings in this study -- reported in the August issue of the Journal of Abnormal Psychology -- and subsequent work, the researchers have begun a project measuring brain activity in combat veterans suffering from post-traumatic stress syndrome.

In the study, 40 students were split into groups based on levels of reported trait anxiety, which is associated with a tendency toward anxious arousal and panic. As the students listened to narratives that depicted pleasant, unpleasant, arousing or non-arousing events, researchers measured brain activity.

Previous research on anxiety has yielded often contradicting and unexplainable results, with electrical activity fluctuating between the brain's left and right hemispheres. The new findings, said U. of I. psychologist Wendy Heller, may clear up the confusion.

"Worry seems to be associated more with verbal ruminating, obsessing or making up stories in your head," she said. "Panic is much more a physiological state of alertness in which a person responds to a perceived threat with heart pounding, hands sweating, light-headedness and/or dizziness.

"It's been right there in the literature. Most of the studies that found more right-hemisphere activity were looking at panic or some kind of stressful state," she said. "Most of the studies that found more left-hemisphere activity were looking at worry. Now we have a possible explanation for this very bizarre pattern in the literature."

A clearer picture of right-hemisphere involvement in emotional responses to the environment is emerging, Heller said. "It also may turn out to play a role in anxiety disorders in general. In post-traumatic stress, for example, a person becomes hypervigilant. We know the threat system is activated. The puzzle is coming together, allowing us to begin looking for the mechanism."

The findings in Abnormal Psychology were reported by Heller, doctoral students Jack B. Nitschke and Marci A. Etienne, and Gregory A. Miller, a professor of psychology. A related study, done by Heller, Nitschke and Dr. Dana L. Lindsay, a U. of I. medical student who now is at the University of Texas Southwestern Medical Center in Dallas, appeared in the journal Cognition and Emotion. Heller also detailed a subsequent, unpublished study at the Fourth Laterality and Psychopathology Conference in London in June. The work was supported by the National Institutes of Mental Health.

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