Isolation and social exclusion, in older men, in 40-year-old males and females, and in children, are associated with: (1) a typical psychological profile, characterized by anxiety, fear of receiving negative evaluations from others, and extreme sensitivity to rejection; (2) a strong increase (doubling) in the levels of inflammatory markers (C-reactive protein (CRP) and interleukins); and (3) and a remarkable reactivity of the immune system to both social and natural stressors (e.g., seeing a snake attacking). Here, CRP is linked to Anxiety.