Australian researchers have developed the world’s first potential blood test to help diagnose mood disorders like depression, simply by measuring levels of a specific protein found in the brain.
Scientists have long known that psychological stress is related to lower levels of a certain brain protein called mature BDNF (mBDNF), and that reduced levels are also associated with depression. But commercially available blood tests have been unable to differentiate between mBDNF and other forms of the protein.
In cooperation with scientists in China, a team from the University of Adelaide developed a type of test called an enzyme-linked immunosorbent assay, or ELISA, which uses antibodies to detect the presence of specific proteins. They applied this new test to blood samples from more than 100 patients with depression or bipolar disorder, and a control group of about 100 people with no mental illness.
The testing found clear links between low blood levels of mBDNF and mood disorders – and the more severe depression that patients reported, the lower their mBDNF levels were. Levels in patients not currently taking antidepressants were also found to be lower than in those being treated with medications.
The study data, which was published in the Journal of Psychiatric Research, showed that the test has an accuracy rate of 80-83%, and also establishes a cutoff point below which one of these disorders is likely. Its authors said the test may soon serve as an “objective biomarker” that could be used, along with clinical assessment by a doctor, to both diagnose mood disorders and monitor the success of treatment.