Researchers say they have developed a blood test that may reliably detect depression. Experts say it could become one of the first objective ways to assess depression via hormones, growth factors and proteins. “Psychiatry is a field that is begging for tests because all of our diagnoses, for the most part, are based on clinical assessments, and clinical assessments are very subjective and can be biased,” says Jennifer L. Payne, MD, a psychiatrist and co-director of the Mood Disorders Center at Johns Hopkins Hospital in Baltimore. The study was published in the journal Molecular Psychiatry. Another study, involving 70 people with depression (and 43 people who were not) correctly identified depression about 91% of the time, ruling it out 81% of the time. “Chronic inflammation is a big risk factor or part of the process of depression itself,” says an associate professor of psychiatry at Harvard Medical School. Additional indicators include hormones, growth factors, enzymes, and other proteins that act as chemical messengers.