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MRI reveals relationship between Depression
and Pain
Newswise — The brains of individuals with
major depressive disorder appear to react
more strongly when anticipating pain and
also display altered functioning of the
neural network that modifies pain
sensitivity, according to a report in the
November issue of Archives of General
Psychiatry, one of the JAMA/Archives
journals.
“Chronic pain and depression are common and
often overlapping syndromes,” the authors
write as background information in the
article. Recurring or chronic pain occurs in
more than 75 percent of patients with
depression, and between 30 percent and 60
percent of patients with chronic pain report
symptoms of depression
“Understanding the neurobiological basis of
this relationship is important because the
presence of comorbid pain contributes
significantly to poorer outcomes and
increased cost of treatment in major
depressive disorder.”
Irina A. Strigo, Ph.D., of the University of
California San Diego, La Jolla, and
colleagues studied 15 young adults with
major depressive disorder (average age 24.5)
who were not taking medication and 15
individuals who were the same age (average
24.3 years) and had the same education level
but did not have depression.
Patients with depression completed a
questionnaire that evaluated their
tendencies to magnify, ruminate over or feel
helpless in the face of pain.
All participants underwent functional
magnetic resonance imaging (fMRI) while
their arms were exposed to a thermal device
heated to painful levels (an average of 46.4
degrees to 46.9 degrees Celsius, or about
115 degrees to 116 degrees Fahrenheit) and
also to non-painful temperatures.
Visual cues (a green shape for non-painful
warmth and a red shape for painful warmth)
were presented before the heat was applied.
Compared with the controls, patients with
depression showed increased activation in
certain areas of their brain—including the
right amygdala—during the anticipation of
painful stimuli.
They also displayed increased activation in
the right amygdala and decreased activation
in other areas, including those responsible
for pain modulation (adjusting sensitivity
to pain), during the painful experience.
To examine whether the activation of the
amygdala was associated with passive coping
styles, the researchers compared the
percentage change in the activations of the
amygdala with the helplessness, rumination
and ramification reported by the
participants with depression.
“Significant positive correlations were
observed in the major depressive disorder
group between greater helplessness scores
and greater activity in the right amygdala
during the anticipation of pain,” the
authors write.
“The anticipatory brain response may
indicate hypervigilance to impending threat,
which may lead to increased helplessness and
maladaptative modulation during the
experience of heat pain,” the authors write.
“This mechanism could in part explain the
high comorbidity of pain and depression when
these conditions become chronic.”
“Future studies that directly examine
whether maladaptive response to pain in
major depressive disorder is due to
emotional allodynia [a pain response to a
non-painful stimulus], maladaptive control
responses, lack of resilience and/or
ineffectual recruitment of positive energy
resources will further our understanding of
pain-depression comorbidity,” they conclude.
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