Doctors may soon have a more objective way to diagnose and treat depression: a blood test that provides a score between one and nine, with higher scores correlating with an increased probability of a patient having major depressive disorder.
Developed by Ridge Diagnostics, based in San Diego, the test measures changes in 10 biomarkers in the blood and feeds the results into an algorithm that assesses four different body systems to compute the final score.
While advanced blood tests and imaging scans can reveal many diseases at their earliest stages, diagnosing neuropsychiatric disorders typically requires an expert to assess how many subjective symptoms a patient exhibits. As a result, many patients are misdiagnosed or never diagnosed. In 2005, Harvard researchers published a study that indicated that more than 20 million people in the United States suffer from mood disorders, but only about 50 percent have been diagnosed and are being treated.
Doctors have been searching for an objective, biological test for depression “ever since the beginning of clinical psychiatry, 50 or 60 years ago,” says George Papakostas, an associate professor of psychiatry at Harvard Medical School and director of Treatment-Resistant Depression Studies at Massachusetts General Hospital.
Scientists have tried various approaches, including genetic tests, tests that measure hormone stress responses, or brain imaging. They’ve measured possible imbalances in neurotransmitters such as serotonin, norepinephrine, and dopamine, and even measured vocal cues. “There are some signals,” Papakostas says.”The problem thus far is that if you looked at a single element, a single marker or disease area, the signal was weak.”