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activity reflects differences in types of anxiety
Diana Yates, Life Sciences Editor
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by L. Brian Stauffer
|UI psychology professors Gregory A. Miller and Wendy Heller were co-principal investigators on a study that examined two different types of anxiety. Their work appears this month online in Psychophysiology.
CHAMPAIGN, Ill. —
All anxiety is not created equal, and a research team at the University
of Illinois now has the data to prove it. The team has found the most
compelling evidence yet of differing patterns of brain activity associated
with each of two types of anxiety: anxious apprehension (verbal rumination,
worry) and anxious arousal (intense fear, panic, or both).
Their work appears this month online in Psychophysiology.
“This study looks at two facets of anxiety that often are not
distinguished,” said U. of I. psychology professor Gregory A. Miller, co-principal investigator on the study
with psychology professor Wendy Heller. “We had reason to think
there were different brain mechanisms, different parts of the brain
active at different times, depending on what type of anxiety one is
According to a recent national survey, anxiety disorders are the most
commonly reported psychiatric disorders in the U.S. The Diagnostic and
Statistical Manual of Mental Disorders classifies nearly a dozen different
anxiety disorders, from acute stress disorder to obsessive-compulsive
disorder to panic attack and PTSD. But those who study and treat patients
with anxiety disorders do not always differentiate the patients who
worry, fret and ruminate from those who experience the panic, rapid
heartbeat or bouts of sweating that characterize anxious arousal. These
two kinds of anxiety may occur alone or in combination, with potentially
important implications for treatment.
To test whether neural activation patterns supported the hypothesis
that these two categories of anxiety are distinct, the researchers selected
42 subjects from a pool of 1,099 undergraduate college students, using
psychological tests to categorize them as “high anxious apprehension,”
“high anxious arousal,” or neither.
Other psychological assessments standardized the pool of participants
by removing those with mood disorders or other complicating factors.
The researchers used functional Magnetic Resonance Imaging (fMRI) to
map the brain areas with heightened neural activity during a variety
of psychological probes.
As the researchers had predicted, the anxious apprehension group exhibited
enhanced left-brain activity and the anxious arousal group had heightened
activity in the right brain. The anxious apprehension group showed increased
activity in a region of the left inferior frontal lobe that is associated
with speech production. The anxious arousal group had more activity
in a region of the right-hemisphere inferior temporal lobe that is believed
to be involved in tracking and responding to information signaling danger.
Other studies using electroencephalographic (EEG) methods had found
that patients diagnosed with generalized anxiety disorder and obsessive-compulsive
disorder had heightened activity in the left brain, whereas patients
with panic disorder, panic symptoms or those subjected to high stress
situations exhibited enhanced activity in the right hemisphere.
This is the first study, however, to localize the affected regions to
identify areas within each hemisphere that seem to matter.
Miller stressed the importance of a related finding: The researchers
distinguished the left-brain region involved in anxious apprehension
from a nearby structure that is associated with positive emotional processing.
“Left and right is not the only distinction we made,” Miller
said. “We did left/right comparisons with groups, but we also
did comparisons within the left hemisphere to show that these different
areas are doing different things.”
“This is biological validation of the proposal of the psychological
differentiation of types of anxiety,” Miller said. “Whether
you want to treat anxiety psychologically or biologically – and
we know that either type of intervention affects both the psychology
and the biology of the person – these findings are a reminder
that you might want to assess people carefully before you embark on
a particular type of treatment.”
This research is based on a master’s thesis submitted by graduate
student Anna S. Engels to the U. of I. The work was supported primarily
by the National Institute of Mental Health and also by the National
Institute on Drug Abuse, both at the National Institutes of Health.
Support also was provided by the Beckman
Institute, the department of psychology and the Intercampus Research
Initiative on Biotechnology at the U. of I.
affiliated with the Beckman Institute; the department of psychology
and the Neuroscience
Program in the College of Liberal
Arts and Sciences; and the department of psychiatry in the College
Editor’s note: To reach Gregory A. Miller, call 217-333-4507;