Does loneliness lie within? Personality functioning shapes loneliness and mental distress in a representative population sample

Background: Loneliness is a major public health issue and the identification of risk factors is crucial for prevention and intervention. While previous research has often investigated sociodemographic and external factors (e.g., living situation), personality variables received less attention. This study aimed to harness recent advances in the dimensional assessment of personality pathology to expand knowledge about psychological determinants of loneliness in the population. Methods: We surveyed a sample representative of the German population concerning age, gender, and level of education (N = 2412) using measures of loneliness (UCLA 3-item loneliness scale), personality functioning (12-item version of the OPD-Structure Questionnaire OPD-SQS), and mental distress (PHQ-4). We explored the relevance of personality functioning for loneliness in a multivariate linear regression analysis and in a theoretically-based path model in which we tested loneliness as the mediator between personality functioning and mental distress. Results: In the regression analysis, personality functioning showed strong associations with loneliness (β = 0.48, p < .001) (within a model that included gender, age, living situation, income, education, and partnership). The mediation model fit the data well and loneliness mediated 39.9% of the total effect of personality functioning on distress. Limitations: The present findings are based on cross-sectional survey data. Conclusions: This study gives insight into previously understudied individual differences shaping feelings of loneliness and mental health outcomes. It suggests that deficits in personality functioning independently aggravate the risk of experiencing loneliness, hence the conception of risk factors for loneliness should be expanded to include personality variables