Towards the validation of three assessment instruments derived from the PDM P Axis: The Psychodynamic Diagnostic Prototypes, the Core Preoccupations Questionnaire and the Pathogenic Beliefs Questionnaire.

Objective: The aim of this paper is to explain the procedures used and show the results obtained from an empirical study of the assessment of personality disorders using three empirical instruments derived from the Axis P of the Psychodynamic Diagnostic Manual (PDM) (PDM Task Force, 2006): the Psychodynamic Diagnostic Prototypes (PDP), the Core Preoccupations Questionnaire (CPP) and the Pathogenic Beliefs Questionnaire (PBQ). Methodology: Six graduate students in clinical psychology, who were working on their dissertation theses in Clinical Assessment and Diagnosis and were enrolled in clinical training provided by the Italian National Health System, were trained by experts to perform diagnoses using the PDM. They performed a systematic interview for personality assessment, the Clinical Diagnostic Interview (CDI) (Westen & Muderrisoglu, 2003) with 200 patients who were receiving psychological and/or pharmacological treatments by clinicians who worked in the Mental Health Units of the National Health System. These patients were assessed using the DSM-IV-TR Axis II criteria and the new instruments to be validated. The clinicians who were treating these patients independently assessed them with the same instruments on the basis of their knowledge of the patients. Eventually, raters and clinicians utilized a specific clinical form for gathering information about their work and their patients. Results: The results of this study seem to support the empirical soundness (face validity, cross-informant/cross-method reliability, convergent, discriminant and concurrent validity) and the clinical usefulness of the PDP, CPQ, and PBQ. Conclusion: The results of this study seem to support the reliability and validity of the new instruments derived from the PDM.