Advancing the diagnosis of major depressive disorder by adding a biological perspective: key considerations for developing a biomarker panel for MDD

Major depressive disorder (MDD) is a psychiatric disorder with a high disease burden impacting not only patients but also healthcare. Current diagnostic methods primarily rely on professional standards and guidelines, with limited incorporation of biological factors. Introducing a biological perspective to the diagnosis of MDD might enhance diagnostic accuracy, facilitate treatment initiation and effectiveness thereby improving quality of life and reducing healthcare costs. Over the years accumulated research into the biological background of MDD resulted in the postulation of several hypothesis believed to play a role in MDD pathophysiology. With the elucidation of MDD pathophysiology biomarkers were also found with the potential to be utilized in a diagnostic environment. This thesis is split in two parts. Part one focuses on some key considerations for developing a biomarker panel for MDD by looking at the fundamentals of biomarker discovery and biomarker methodology within a clinical environment. Part two focusses on the essentials of biomarker panel model development and validation towards clinical applications.