Elevated threat-sensitivity and reduced reward-sensitivity associated with increased peripheral inflammation among young adults

Objectives: Elevated threat-sensitivity (i.e., neuroticism) and dampened reward sensitivity have both been linked with elevated inflammation – a known risk factor for mental and physical and health related problems. Research has yet to examine the nature of the relationship between threat and reward sensitivity in predicting inflammation. Drawing on existing research, the present study predicted that individuals with elevated threat sensitivity and attenuated reward sensitivity would be most likely to display elevated inflammation. Method: One hundred and fifty-two participants aged 18 to 19 (female = 92) were drawn from an ongoing study of the relationship between threat- and reward-sensitivity and mental and physical health. Recruitment strategies were designed to maximize variance in both threat and reward sensitivity. Threat-sensitivity was assessed using the Eysenck Personality Questionnaire Neuroticism subscale, and reward sensitivity by the Behavioral Activation System (BAS) Total scale. To measure circulating inflammatory proteins, aspirated serum from an antecubital venipuncture was assayed in duplicate with MSD Meso Scale Discovery Human ProInflammatory 7-Plex Base Kits, and an inflammation composite score was computed from levels of IL-6, IL-8, IL-10, and TNFa. Age, gender, and ethnicity were included as covariates. Results: In line with prediction, there was a significant interaction between self-reported threat- and reward-sensitivity in predicting inflammation (b = -1.27, t = -1.95, p < .05), such that individuals with elevated neuroticism and reduced reward sensitivity displayed the highest levels of inflammation as indexed by a composite score. Conclusions: The present study is the first to examine the relationship between threat- and reward-sensitivity in modulating peripheral inflammation. Results show that individuals with both elevated threat-sensitivity and reduced reward sensitivity display the greatest levels of peripheral inflammation. These results are in line with the recently developed Neuroimmune Network (NIN) model which proposes that elevated threat-sensitivity and attenuated reward-sensitivity facilitate self-medicating behaviors typically associated with elevated inflammation. Specific patterns across different domains of reward seeking patterns as well as changes in neuroticism over time will be discussed.