Rafting toward a depression biomarker.

The journey from the cytoskeleton and G protein signaling to a framework that might provide a simple blood diagnostic for depression as well as a harbinger of individual antidepressant response, has been convoluted, occasionally frustrating, but ultimately rewarding. Herein, I provide a travelogue of sorts on our progress toward this end, and also chart a course toward the goal of providing a simple, quantitative and objective, biomarker-driven assessment tool that reflects the neurobiology of depressed mood.