Table 1.

Biopsychosocial approaches to loss associated with depression.

Model	Authors	Theory
Affective neuroscience approach to depression	Jaak Panksepp and Douglas Watt	Sustained and prolonged activation of the GRIEF system leads (by a yet-unknown mechanism) to inhibition of the reward-seeking system. Inhibition of the reward-seeking system in rats manifests as surrender and defeat in different tasks (used to measured depression phenotype), which Panksepp and Watt conceptualized as anhedonia—one of the primary symptoms of major depressive disorder (MDD).
Social signal transduction theory	George Slavish and Michael Irwin	Prolonged early stress (such as loss) is a predictor of MDD and dysregulation of inflammatory processes in chronic health conditions.