Scientists are scanning brains of patients with depression, drawing their blood, asking about their symptoms, and then scouring that data for patterns. The goal: pinpoint subtypes of depression, then figure out which treatments have the best chance of success for each particular variant of the disease. But it’s not an easy task to break down the many factors that contribute to depression into clean categories with clear treatments. While some in the field are excited about the promise of precision medicine to better tailor treatments for depression, others are worried the idea is being overhyped. “It remains to be shown that depression coalesces into neat subcategories, as opposed to being a fuzzy set,” said Dr. Steven Hyman, director of the Stanley Center for Psychiatric Research at the Broad Institute of MIT and Harvard. Bringing precision medicine to depression would be difficult for the same reason it would be useful — depression is a heterogeneous disease that varies wildly from one patient to the next.