Understanding the role of neuroticism facets and socioeconomic status in adulthood mortality risk

Introduction

Neuroticism is a personality trait characterised by the tendency to experience negative emotions. High levels of neuroticism have been linked to poorer physical and mental health outcomes; however, findings on mortality risk have been inconsistent. The research described in this thesis explored the facets of neuroticism and their association with mortality risk. In addition, socioeconomic status was also explored as a possible mediator of this association. The aims of the thesis were twofold and, therefore, addressed in two separate studies. The first study is a systematic review and narrative synthesis of the quantitative literature examining neuroticism facets and risk of mortality. The second study is an empirical study investigating the association between neuroticism facets and mortality risk, mediated by socioeconomic status, using an established longitudinal dataset.

Method

Six electronic bibliographic databases were searched for eligible studies using keywords encompassing personality traits and mortality for the systematic review study. Articles from inception to January 2023 were reviewed. The risk of bias was assessed using a modified Newcastle-Ottawa Scale. Five studies were identified for inclusion in the review, and a narrative synthesis was performed to synthesise the findings of these studies. In the empirical study, a survival analysis using Cox proportional hazards regression was carried out to ascertain whether neuroticism facets predicted mortality risk in a sample of participants from the Seattle Longitudinal Study. A mediation analysis was also conducted to explore whether socioeconomic status mediated this association.

Results

The systematic review findings were mixed and indicated that research in the area is limited in frequency and that there is a large variability between studies. Certain facets of neuroticism were linked to a potential increase and decrease in mortality risk. Two studies reported facets linked with increased mortality risk, two reported facets with a protective effect, and one reported no association. The findings of the empirical study suggested that socioeconomic status provided an indirect pathway between the facet of vulnerability and the risk of mortality.

Conclusions

The review outcomes suggest that multiple facets of neuroticism are essential to consider in exploring the effects of personality on mortality risk. Due to the diverse nature of the facets and the results presented, the systematic review highlights the need for future rigorous research and outlines suggested recommendations to improve reliability and validity and to allow for comparability of findings. In the empirical study, no direct effects were found, but an indirect pathway linking vulnerability to the risk of mortality was found through socioeconomic status. This work highlights the importance of investigating indirect pathways that link neuroticism facets to mortality risk. Implications of this research are discussed at length throughout.