J Psychiatry Neurosci 2013;38(2) 75 Editorial A way forward for research on biomarkers

Webster’s New World Medical Dictionary provides a simple def inition of a biomarker as “a biologic feature that can be used to measure the presence or progress of disease or the effects of treatment. ” In the research literature, the term “can-didate biomarker ” is often loosely applied to any biological feature associated with a disorder. The search for biomarkers for psychiatric disorders has a long history, with earlier studies investigating molecular markers, like platelet imip-ramine binding or cerebrospinal 5-hydroxyindoleacetic acid (5-HIAA) in people with depression, or behavioural markers, such as smooth pursuit eye movements in people with schizo phrenia. More recent searches continue to look for blood biomarkers (e.g., brain-derived neurotrophic factor and cytokines in people with schizophrenia or depression) and behavioural biomarkers (e.g., fear extinction in peopl