April Flowers for redOrbit.com – Your Universe Online
Typically, diagnosing depression involves discussions about symptoms with a doctor or a therapist. It isn’t an exact science, because until now, there wasn’t an empirical test for most mental illnesses. A new study from the Medical University of Vienna (MedUni Vienna) might just change that. The study findings, published in PLOS ONE, demonstrate that in principle it might be possible to use a blood test to detect depression.
The transport of the neurotransmitter serotonin, known for improving mood, into a cell is facilitated by a protein in the cell membrane called a serotonin transporter (SERT) — which regulates neural depression networks. A lack of serotonin is often to blame for depressive conditions, making SERT the target of choice for many anti-depression drug therapies.
SERT is not just present in the brain, but also occurs in large quantities in organs such as the intestines or the blood. The SERT present in blood makes sure that blood platelets maintain the proper concentration of serotonin in the blood plasma, working identically to the way it performs in the brain.
The MedUni Vienna team, which included Christian Scharinger and Ulrich Rabl, working under the supervision of Lukas Pezawas at the Department of Biological Psychiatry, University Department of Psychiatry and Psychotherapy, and others, used functional magnetic resonance (fMRI) images of the brain, in conjunction with pharmacological investigations to demonstrate a close relationship between the speed of serotonin uptake in blood platelets and the function of a depression network in the brain.
Because it is primarily active at rest, and processes content with strong self reference, the network is called the “default mode network.” Recent studies have revealed that the network is actively suppressed during complex thought processes, which is essential for adequate levels of concentration. Patients who suffer from depression have a difficult time suppressing the network during thought processes. This leads to negative thinking and poor concentration.
“This is the first study that has been able to predict the activity of a major depression network in the brain using a blood test. While blood tests for mental illnesses have until recently been regarded as impossible, this study clearly shows that a blood test is possible in principle for diagnosing depression and could become reality in the not too distant future,” explained Pezawas. Being able to detect the processes of the depression network through a blood tests makes it a very real possibility that a blood test for diagnosing depression could be in our near future.