HETODEP · Bringing the field of psychiatry forward: Unraveling heterogeneity of Depression

Depression is a highly prevalent disorder associated with substantial costs, and predicted to be the leading cause of disability in 2030. Although there has been substantial progress in our understanding of the biological processes and environmental exposures associated with mood disorders, application of newer technologies such as neuroimaging and molecular biology have not resulted in major breakthroughs in our understanding of depression, particularly with respect to treatment. One of the major reasons for this lack in breakthroughs is the substantial heterogeneity of major depression. In-depth characterization of biological correlates of subtypes can inform our understanding of the sources of heterogeneity that may index different etiological pathways. In addition, clinical presentation of depression forms an important component in research on depressive subtypes. Recent evidence suggests that disturbances in activity, sleep, appetite and circadian patterns may be more important than mood changes as core features of depression, but measurement of these domains relies on self-reported, retrospective assessments. Objective ambulatory methodologies, including Actigraphy and ecological momentary assessment (EMA), may be valuable in defining the core features of depression subtypes more accurately. In addition, these technologies are relevant to future research and clinical practice through applications in interventions and continuous patient monitoring.This proposal aims to unravel the heterogeneity of depression by: 1) Systematical characterization of depressive subtypes on a wide range of biological measures to increase insights into the differential etiology of depressive subtypes and bring us one step closer to improved treatments, and 2) Incorporation of accurate, objective, and valid assessment of the core features and differentiators of depression subtypes using innovative ambulatory monitoring technologies, and use of these to validate depressive subtypes.