Our findings replicate and extend previous research on the association between personality and IL-6. Consistent with the depression literature (Penninx et al. 2003; Davidson et al. 2009), trait Neuroticism was associated with higher levels of IL-6, as was the hostility facet, which has also been associated with greater IL-6 (Marsland et al. 2008). Although some have not found an association between IL-6 and Neuroticism (e.g., Chapman et al. 2009), this may be due to differences in sampling strategies (e.g., age distribution, community versus patient, etc). In addition, large samples are necessary to be able to detect small effects reliably. Finally, consistent with Chapman and colleagues (2009), the activity component of Extraversion was associated with lower levels of IL-6, whereas the positive affect aspects of this trait were not. To our knowledge, we are the first to report an association between IL-6 and Conscientiousness.
