Today, psychiatrists must diagnose mental illnesses by asking patients a series of questions—perhaps over many sessions. But an Indiana University psychiatrist is trying to develop blood tests that would quickly and objectively diagnose patients suffering from depression and bipolar disorder.

Dr. Alexander B. Niculescu, a psychiatrist at the IU School of Medicine, has won a five-year, $1.5 million grant from the National Institutes of Health to hunt for the presence of certain proteins in the blood that would indicate that a person suffers from a mood disorder, which afflicts one in five Americans.

“There is a strong need for a move towards comprehensive empirical testing and away from categorical diagnostic classifications,” according to the website for Niculescu’s lab. His team says its mission is “personalized psychiatry.”

The subjective nature of mental illness has always led to some doubt—both in medicine and in the general public—about the reality of mood disorders. The antidepressant Prozac, made by Eli Lilly and Co., is credited with revolutionizing the field in 1988 because it convinced many physicians that the disease was real.

Still, each individual antidepressant drug appears effective in a minority of the patients who take it. Scientists and pharmaceutical companies hope that by identifying the role of differing genes and proteins in different patients, they can tailor drugs more specifically to patients who benefit from them.