Up to one million
Australians suffer from social
phobia at any one time, making it
the most common anxiety disorder,
and the third most common
psychiatric disorder after
depression and alcohol dependence.
People with
generalized social phobia experience
heightened anxiety during potential
or perceived threatening social
situations. They generally avoid eye
contact and fear any interpersonal
situation.
The research, to
be published in the journal
Biological Psychiatry, was conducted
by an international team of
researchers, including Associate
Professor Pradeep Nathan from Monash
University's Centre for Brain and
Behaviour and the Department of
Physiology.
The researchers
found that the area of the brain
called the amygdala becomes
increasingly hyperactive when
patients look at threatening, angry,
disgusted or fearful faces. Further,
they found that the increased
response in the amygdala correlated
with the patients' level of social
phobia symptoms.
The amygdala is in
the limbic part of the brain, which
controls emotions and sends messages
to the parts of the brain
controlling breathing and heart
rate.
Using functional
magnetic resonance imaging, the
researchers compared brain activity
when people with generalized social
phobia looked at threatening faces
compared to happy or neutral faces.
Dr Nathan said the
study showed that functional
magnetic resonance imaging could be
used to monitor activity in the
amygdala and therefore predict the
level of clinical symptoms in
generalized social phobia patients.
"Our findings
suggest that amygdala activation to
interpersonal threat can be
specifically linked to the severity
of social anxiety symptoms of
individual patients with generalized
social phobia," he said. Thus, it
may serve not only as a useful
functional marker of disease
severity, but also as a marker of
the effectiveness of pharmacological
and psychological treatments."
The study was done
by Dr Nathan in conjunction with
lead author Dr Luan Phan and Dr
Daniel Fitzgerald from the
University of Chicago and Dr Manuel
Tancer from Wayne State University.
