Between Normal and Abnormal Personality – Examining the Joint Structure of the IPIP-NEO-120 and the PID-5

Abstract: Objective: The overlap of normal and abnormal personality and personality disorders was found on facet and domain level, but only a few studies assessed the higher order joint structure. In this study, the Personality Inventory for the DSM-5 (PID-5-100 item form) and the IPIP-NEO-120 are assessed in their internal consistency, convergent and discriminant validity and their joint structure, modelled as the overlap of the General Factor of Personality (GFP) and p-factor. Method: The IPIP-NEO-120 and PID-5-100 are examined in their scale consistencies, and validity is assessed with Spearman ρ coefficients and confirmatory factor analyses (CFA). The overlap of both instruments was modelled with a Canonical Correlation (CCA) and in a Structural Equation Modelling (SEM) framework. Results: The IPIP-NEO-120 showed high reliabilities and expected convergence with the Five Factor Model (FFM). The PID-5-100 showed moderate reliabilities and differentiated results for the facet structure. It converged well for most factors with the proposed structure, indicating a reliable and valid use of the 100 item form. The CCA indicated an overlap of 55%. On higher order level, the structure displayed high convergence (β = -0.89), although the factor Openness had no influence on the GFP. The results are pointing towards the existence of a mutual construct of normal and abnormal personality. Conclusion: The PID-5-100 showed comparable results to the original long version. The high convergence of normal and abnormal personality is discussed as “Big Everything” of personality and psychopathology, or a methodological artefact, such as social desirability.