Clinical depression can be a difficult disease to treat since there is no perfect way to select which antidepressant will be best for the patient. Often times psychiatrists will have to go through one drug and then another until an individual responds and that may take many months. Several studies in the past few years have discovered blood-based biomarkers of depression giving hope that better diagnosis and treatments for depressed patients can be attained. Now a study in the Archives of General Psychiatry has uncovered an inflammatory protein, C-Reactive protein, which when elevated in the blood indicated that study participants would respond to treatment. While the drug being investigated (Infliximab) did not initially appear to work, a review of the data demonstrated that 62% of the patients with elevated CRP responded compared to 33% with low levels of the marker.