Biomarkers for Depression: Recent Insights, Current Challenges and Future Prospects

Abstract

A plethora of research has implicated hundreds of putative biomarkers for depression, but has not yet fully elucidated their roles in depressive illness or established what is abnormal in which patients and how biologic information can be used to enhance diagnosis, treatment and prognosis. This lack of progress is partially due to the nature and heterogeneity of depression, in conjunction with methodological heterogeneity within the research literature and the large array of biomarkers with potential, the expression of which often varies according to many factors. We review the available literature, which indicates that markers involved in inflammatory, neurotrophic and metabolic processes, as well as neurotransmitter and neuroendocrine system components, represent highly promising candidates. These may be measured through genetic and epigenetic, transcriptomic and proteomic, metabolomic and neuroimaging assessments. The use of novel approaches and systematic research programs is now required to determine whether, and which, biomarkers can be used to predict response to treatment, stratify patients to specific treatments and develop targets for new interventions. We conclude that there is much promise for reducing the burden of depression through further developing and expanding these research avenues.

From feedback loop transitions to biomarkers in the psycho-immune-neuroendocrine network: Detecting the critical transition from health to major depression

“…In recent times there has been recognition of the importance of examining groups or panels of biomarkers, rather than investigating individual markers, in relation to chronic stress (Juster, McEwen, & Lupien, 2010) or MDD (Domenici et al, 2010;Strawbridge, Young, & Cleare, 2017). It has been recommended that large groups of biomarkers across different modalities be studied in concert, and that advanced mathematical modelling, machine learning and pattern recognition methods be used to analyze such biomarker groupings and their relation to diseases such as MDD (Kennedy et al, 2012;McEwen, 2015).…”

Increased cancer-specific mortality in individuals developing mental disorders after cancer diagnosis: biomedical factors versus psychosocial support

“…First, however, it is important to analyze, with high granularity, the association between first onset of mental disorders and poor cancer outcomes in patients with and without treatment for mental illness and/or cancer. Certainly, a growing body of literature associates mental conditions with stress-related biomarkers (6), perhaps compounding the inflammatory milieu seen with cancer. In fact, the association between stress and psychosocial factors with cancer incidence, survival, and mortality has been demonstrated previously (7).…”

A systematic review of the overlap of fluid biomarkers in delirium and advanced cancer-related syndromes

“…The top five most commonly studies biomarkers in this review were inflammatory biomarkers, namely, CRP, IL-6, TNF-α, IL-10 and IL-8. The challenge with inflammatory markers is that they are nonspecific and the inflammatory pathways are similar to those implicated in other conditions such as sepsis and depression [181,182]. Likewise, of the six delirium studies where there was concomitant cancer, it is very difficult to determine whether those biomarkers found were related to the cancer or the delirium itself, considering alterations in inflammatory pathways are implicated in both.…”