Blood-based biomarkers in psychiatric diseases

Identification of blood-based biomarkers for psychiatric disease risk and development has emerged as an important area of translational research in medicine, offering a means to supplement or replace current interview-based methods for psychiatric diagnosis. The aim of this thesis is to assess the utility of genome-wide blood transcriptome profiling for the prediction, diagnosis and treatment of patients with psychiatric diseases. Some parts of this work are of a more methodological nature and geared towards the discovery of blood-based biomarkers and gene networks, while others consider mechanistic and translational implications. Overall, this work contributes to understanding the pathophysiology of major psychiatric diseases and to the development of new biomarkers and treatments. Part I discusses the current transition from interview-based psychiatric diagnostics towards genomic-based interventions (Chapter 1) prior to introducing experimental methodologies (Chapter 2) and statistical approaches (Chapter 3) that may provide favorable translational avenues for blood biomarker discovery in psychiatry. Part II contains four investigations (summarized in Chapter 4) that apply genome-wide transcriptome profiling of patient blood samples in pursuit of blood-based biomarkers and gene networks implicated in posttraumatic stress disorder (Chapter 5), acute psychological stress (Chapter 6), methamphetamine-associated psychosis (Chapter 7) and treatment response in bipolar disorder (Chapter 8). Part III proposes a set of rules or postulates for accelerating the identification of reliable and accurate blood-based biomarkers in patients with psychiatric diseases (Chapter 9