Psychobiological mechanisms linking spousal bereavement and health from the perspective of the Social Signal Transduction Theory of Depression (20). The interplay between genetic factors, personality traits (e.g., neuroticism), and social-environmental conditions during childhood and adolescence (e.g., social/financial stress, uncertainty, abuse, or neglect) are hypothesized to play important roles in shaping individuals' neuro-inflammatory sensitivity to later-occurring life stressors, including interpersonal loss. Exposure to early life stress and subsequent stressors are hypothesized to heighten sympathetic nervous system and hypothalamic-pituitary-adrenal axis dysregulation, and to promote increased inflammatory activity in response to a significant loss. If chronic, elevated inflammatory activity can in turn lead to a variety of adverse emotional, behavioral, and health outcomes. SNS, sympathetic nervous system activation; NE, norepinephrine; EPI, epinephrine; HPA, hypothalamic-pituitary-adrenal; GC, glucocorticoid; IL-1, interleukin-1; IL-1β, interleukin-1beta; IL-6, interleukin-6; IL-6R, interleukin-6 receptor; IL-12, interleukin-12; TNF-α, tumor necrosis factor-α.