Personality disorder diagnostic thresholds correspond to different levels of latent pathology.

To meet a diagnosis for a particular personality disorder (PD), among other requirements, a person must exhibit a specified minimum number of the features outlined for that PD, otherwise referred to as the diagnostic threshold. Despite many years of research on the DSM PDs, there is little empirical basis for the chosen thresholds. The present study used mechanisms of item response theory (IRT) to link the diagnostic thresholds of six PDs to their corresponding level of latent PD pathology. Consistent with our hypothesis, analyses of the data from 41,227 participants revealed that PD diagnostic thresholds corresponded to a wide range of latent pathology. For example, the diagnostic threshold for schizoid PD corresponded to 1.54 SDs of pathology whereas the threshold for dependent PD corresponded to 2.72 SDs of pathology. The current analyses have demonstrated for the first time that the latent pathology associated with each PD threshold varies widely, and thus has quantified what others accurately have speculated. Implications and considerations for the future directions of PD classification are discussed.