February 2, 2012
Diagnosing Clinical Depression With A Blood Test
A new blood test has been developed which can accurately distinguished patients diagnosed with depression from control subjects, reports a study published in the journal Molecular Psychiatry.
Dr. George Papakostas, an associate professor of Psychiatry at Harvard Medical School, explained that previous efforts to develop tests based on a single blood or urinary biomarker were insufficiently sensitive but this new test has achieved desired results, reports UPI.Study co-author John Bilello, chief scientific officer of Ridge Diagnostics, which sponsored the current study says, "The study authors note that previous efforts to develop tests based on a single blood or urinary biomarker did not produce results of sufficient sensitivity, the ability to detect the tested-for condition, or specificity, the ability to rule out that condition.”
“The biology of depression suggests that a highly complex series of interactions exists between the brain and biomarkers in the peripheral circulation.”
The test measures biomarkers associated with factors such as inflammation, the development and maintenance of neurons and the interaction between brain structures involved with stress response and other key functions.
The measurements are combined using a specific formula to produce a figure called the MDDScore -- a number from 1 to 100 indicating in percentage form the likelihood that an individual has major depression. Clinical use the MDDScore would range from 1-10.
The initial pilot phase of the study enrolled 36 adults who had been diagnosed with major depression at the MGH, Vanderbilt University or Cambridge Health Alliance in Cambridge, Mass., along with 43 control participants from St. Elizabeth´s Hospital in Brighton, Mass.
MDDScores for 33 of the 36 patients indicated the presence of depression, while only 8 of the 43 controls had a positive test result.
A second replication phase enrolled an additional 34 patients from the MGH and Vanderbilt, 31 of whom had a positive MDDScore result. Combining both groups indicated that the test could accurately diagnose major depression with a sensitivity of about 90 percent and a specificity of 80 percent.
“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,” Bilello concluded. “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.”
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