Beyond the Statistics: Expert Perspectives on the Debate About the Incremental Validity of the AMPD Criteria

The Alternative Model for Personality Disorders (AMPD) proposes a dimensional framework with two core criteria: Criterion A (personality functioning) and Criterion B (maladaptive traits). Debate remains regarding their incremental validity, with prior studies producing mixed results. This study employed a Delphi method with 17 experts in personality disorders (PDs) to evaluate the conceptual, discriminative, clinical, and informative value of both criteria. Consensus indicated that Criterion B captures individualized trait expressions, while Criterion A was seen as global or individualized, depending on use of total or subscale scores. Both criteria were viewed as having stable and dynamic aspects. Experts noted Criterion A's overlap with general psychopathology, while Criterion B was seen to include both PD-specific and broader traits. Criterion A was mainly associated with informing treatment intensity, and Criterion B with guiding therapeutic style. Both criteria were seen as informative for several mental health outcomes. Despite overlap, most experts opposed merging the criteria.