Biomarker-based treatment selection: A precision medicine approach for depression

Among treatment-seeking patients with depression, approximately two thirds of individuals do not remit following first-line therapeutic treatment, likely because of the inherent heterogeneity of major depressive disorder. Identification of clinical or biological features that predict how a patient will respond to treatment could enhance the remission/response rate and reduce unwanted side effects. While many studies have reported on predictors of treatment response, relatively few have focused on moderators or mediators of treatment response-i.e., characteristics that have predictive value regarding how a patient will respond differentially to specific medications. Biological markers of depression-such as genetics, neurophysiology, blood-based markers, and brain activity-enable objective measurement or characterization and may represent ideal biomarkers for predicting differential treatment response. In this chapter, we discuss ongoing and recently completed clinical trials that focus on progressing precision medicine in depression.