International Journal of Comparative Psychology

Accumulating evidence suggests that exposure to psychological stressors leads to increased expression of pro-inflammatory cytokines and activation of inflammatory-related pathways in the central nervous system. Several logical predictions arise from these findings: (1) stressor exposure should produce changes in behavior that are reminiscent of acute illness; (2) administration of antiinflammatory agents should ameliorate some behavioral consequences of stressor exposure; and (3) there should be convergence between anatomical and neurochemical pathways activated by stressor exposure and those involved in mitigating sickness behaviors. Importantly, these predictions have been tested in our laboratory across multiple stressor paradigms (footshock, maternal separation, and during acute alcohol withdrawal) using two species (rats and guinea pigs), suggesting that sickness may represent a more general motivational state that can be elicited by a diverse range of psychological challenges. Implications of these findings for understanding stress-related changes in behavior, mood and neuroinflammatory processes will be discussed with special reference to implications for the individual and reproductive fitness.