Different
brain activity in treatment-resistant
depression
In
spite of the wide range of antidepressant
medication available, approximately 30-40% of
depressed patients fail to respond to these
treatments. In an attempt to elucidate the
reasons why these people do not respond to
currently available therapy a recent study
investigated, in treatment-resistant depressed
patients, dysfunction in different parts of the
brain, known to be involved in affect and mood
states.
Patients with unipolar, treatment-resistant
depression and healthy volunteers viewed a
series of images containing a picture and a
caption while the investigators observed their
emotional reaction using functional magnetic
resonance imaging which can track brain activity
and elucidate areas of the brain used in
specific tasks.
Emotional responses to the images was different
in depressed patients compared to the healthy
individuals. Some regions of the brain were less
active whereas others showed geater activity in
depressed patients. Activitiy in some regions
were reduced in depressed subjects in response
to both negative and positive images or in
others to positive images. In contrast increased
response was found in some areas with negative
images and in others with positive images.
There was a clear association between hypo- and
hyperactivity of some specific brain regions and
non-responsiveness to treatment in depression.
Currently patients resistant to conventional
treatment for depression have few therapeutic
options include psychosurgery and
electroconvulsive treatment. This study may help
to improve understanding of the biological basis
of treatment-resistant depression and enable the
development of medication which may be
efficacious in resistant depression. Biol
Psychiatry 54: 777-791, 2003