Depression diagnosis through blood testing
By Liz Lockhart
Could blood tests be the way forward in the diagnosis of depression? According to a team of researchers 
from Massachusetts General Hospital blood tests it may well be.
The researchers conducted a new study and report that a blood test analysis of the levels of nine biomarkers can accurately identify patients diagnosed with depression.
Lead author of the report, Dr. George Papakostas, said ‘Traditionally, diagnosis of major depression and other mental disorders has been made based on patients’ reported symptoms, but the accuracy of that process varies a great deal, often depending on the experience and resources of the clinician conducting the assessment. Adding an objective biological test could improve diagnostic accuracy and may also help us track individual patients’ response to treatment.’
Co-author of the study, John Bilello, Ph.D., said ‘It can be difficult to convince patients of the need for treatment based on the sort of questionnaire now used to rank their reported symptoms. We expect that the biological basis of this test may provide patients with insight into their depression as a treatable disease rather than a source of self-doubt and stigma.’
The blood test was developed by Ridge Diagnostics. The researchers explain that this test measures the levels of nine biomarkers which are associated with factors which include the development and maintenance of neurons, inflammation and the interaction between brain structures which are involved with stress responses, along with other key functions.
These measurements are then used to produce a figure called a ‘MDD Score’ which is a number that indicated the likelihood of major depression.
The first part of the study used 36 adult participants who had previously been diagnosed with major depression at the Massachusetts General Hospital, Cambridge Health Alliance or Vanderbilt University, together with a further 43 control participants from St. Elizabeth’s Hospital.
The presence of depression was found in 33 of the 36 adult participants, however, only 8 of the 43 control participants were found to have depression.
The second phase of the study involved an extra 34 patients from Massachusetts General Hospital and Vanderbilt. Thirty one of these patients had a positive MDD Score result. According to the researchers, the combination of both groups suggested that the test is accurate in the diagnosis of major depressive disorder with a sensitivity of around 90% and a specificity of 80%. These figures are lower than those for the paper-based tests which are currently used for depression diagnosis.
Papakostas said that determining the true utility of the test will require larger trials – ‘these results are already providing us with intriguing new hints on how powerfully factors such as inflammation, which we are learning has a major role in many serious medical issues, contribute to depression.’
