Molecular biomarkers in depression: Toward personalized psychiatric treatment

Advances in diagnostic technologies have brought the concept of personalized medicine closer to reality, leading to the development and implementation of refined specific therapeutic strategies. While this approach has seen success in areas such as oncology and cardiology, this has been problematic in psychiatry for a variety of reasons, including an incomplete understanding of the underlying pathophysiology of disorders such as depression, as well as the heterogeneity in its clinical presentation. One potential solution to this problem has been to focus on peripheral biomarkers, which are objective physiological indicators of pathological processes. In this chapter, we highlight recent clinical work that has identified candidate biomarkers for depression. We also examine theoretical and practical issues in this context and discuss potential strategies to improve the validity and reliability of biomarkers for clinical use.