Does general intelligence moderate the association between inflammation and psychological distress?

Research has shown that inflammation is implicated in the pathogenesis of mental health disorders, but not all individuals with such disorders have raised inflammatory markers. This study examined whether general intelligence may be a protective factor for 9666 adults aged 18-97 with elevated inflammation, measured with C-reactive protein (CRP), using data from the UK's Understanding Society. In multigroup analyses for males and females, multiple linear regression was used to model psychological distress dependent upon CRP, adjusting for a host of possible confounders including alcohol consumption, smoking status, history of cardiovascular disease or diabetes, physical exercise and obesity. Moderation by intelligence was tested with a multiplicative interaction term. Results showed that, in adjusted models, CRP was related to an increase in psychological distress in males (β = .049) but not females. Furthermore, intelligence moderated the effect of CRP on psychological distress in males (β = −.037), such that males with higher CRP levels were at lower risk with increased intelligence. In conclusion, general intelligence may protect male adults from the negative effects of inflammation on psychological distress.