Could A Diagnostic Blood Test Be Created For Depression?

Psychiatry, unlike many other areas of medicine, lacks diagnostic blood tests. Blood tests have been extremely useful in helping doctors make medical diagnoses and aiding them in treatment options for conditions and diseases in most medical fields.


An article in Biological Psychiatry reports that Dutch researchers may eventually generate blood tests for psychiatric conditions, such as depression.


Under increasingly intensive research by scientists are the studies of:

Variations in DNA (genes) that can be extracted from blood cells
Genomics like proteomics, the measurement of the levels of specific proteins in the blood
Gene expression profiling, which measure the levels of RNA produced from DNA as an indication of the activity of specific genes.

Dutch researchers evaluated blood gene expression profiles in two groups of people:

Patients diagnosed with major depressive disorder (MDD)
Healthy individuals

They identified a set of 7 genes in whole blood that could tell the un-medicated MDD patients from the healthy ones.


Dr. Sabine Spijker, one of the authors, said:



This is a first, but major step in providing a molecular diagnostic tool for depression.



Experts say this type of diagnostic test would be especially useful for diagnosing mental health disorders when it is more difficult to have a conversation with the patient; it would also be unbiased.


The writers add that blood tests of this type may also help in reducing the stigma associated with mental health illness, conditions, and problems.


Dr. John Krystal, Editor of Biological Psychiatry cautions:



It is far too early to be confident that gene expression profiling will lead us to diagnostic or prognostic tests for depression. However, the objective of this line of research is extremely important. In the past, many types of tests have been explored as potential diagnostic markers, but they all have failed to have sufficient sensitivity and specificity to guide doctors in making psychiatric diagnoses or choosing between treatments. I look forward to seeing whether the patterns of gene expression profiling are replicable and diagnostically specific as multiple groups report their findings.


Hopefully, say the authors, this study may be a stepping stone towards finding markers that may predict treatment outcome and recurrence.


"Stimulated Gene Expression Profiles as a Blood Marker of Major Depressive Disorder"

Sabine Spijker, Jeroen S. Van Zanten, Simone De Jong, Brenda W.J.H. Penninx, Richard van Dyck, Frans G. Zitman, Jan H. Smit, Bauke Ylstra, August B. Smit, Witte J.G. Hoogendijk

Biological Psychiatry, Volume 68, Issue 2, 15 July 2010, Pages 179-186