Assessing the overlap of personality traits and internalizing psychopathology using multi-informant data: Two sides of the same coin?

Personality and psychopathology share a hierarchical dimensional structure, developmental trajectories and correlations with varied outcomes. However, quantifying the extent and details of their direct empirical overlap has been hindered by overreliance on self-reports and broad construct domains. Using multimethod data, we estimated the Big Five personality domains' and nuances' (items') "true" correlations (rtrue) with, and true predictive accuracy (rtruePRED) for, various psychopathology state domains, free of single-method and occasion-specific biases, random error, and direct content overlap. Our sample included Estonian Biobank participants (N = 16,226) who completed psychopathology and comprehensive personality questionnaires, and whose personality traits were also rated by close informants. Personality nuances out-predicted the Big Five domains for psychopathology, with items' r_truePRED = .31 … .58 for specific psychopathology domains of distress, fear, inattention, hyperactivity, insomnia, and fatigue, and r_truePRED = .52 for the general p factor. Individual items had various meaningful rtrues with the psychopathology domains. Among the Big Five, neuroticism was the strongest correlate of distress (r_true = .29) and fear (r_true = .13), while inattention was most correlated with conscientiousness (r_true = -.56), hyperactivity with extraversion (rtrue = .25), fatigue with openness (r_true = .12), and insomnia with conscientiousness (r_true = .12). Associations based on self-reports alone were weaker. We argue for multirater and finer grained assessments of both personality and psychopathology to fully reveal the extent and details of their overlap. This association is likely stronger than typical self-report data suggest, yet psychopathology is not empirically redundant with personality traits. (PsycInfo Database Record (c) 2025 APA, all rights reserved).