The first blood test to diagnose major depression in adults has been developed, providing the first objective, scientific diagnosis for depression.
The test measures the levels of nine genetic indicators (known as “RNA markers”) in the blood and can also predict who will benefit from cognitive behavioural therapy, offering the opportunity for more effective, individualised therapy for depression-sufferers. The test also showed the biological effects of the therapy, the first measurable, blood-based evidence of the therapy’s success and showed who is vulnerable to recurring episodes of depression, Northwestern University researchers report.
“The longer this delay is, the harder it is on the patient, their family and environment,” said lead researcher Eva Redei, a professor in psychiatry and behavioural sciences and physiology at Northwestern’s Feinberg School of Medicine in Chicago.
“Additionally, if a patient is not able or willing to communicate with the doctor, the diagnosis is difficult to make,” she said. “If the blood test is positive, that would alert the doctor.”
The test works by measuring the blood concentration of the RNA markers. A cell’s RNA molecules are what interpret its genetic code and then carry out those instructions from DNA. After blood is drawn, the RNA is isolated, measured and compared to RNA levels expected in a non-depressed person’s blood.
The blood test’s accuracy in diagnosing depression is similar to those of standard psychiatric diagnostic interviews, which are about 72 – 80% effective.