Study on the translation and validation of the Personality Diagnostic Questionnaire-Revised (PDQ-R)

The Personality Diagnostic Questionnaire-revised (PDQ-R) is a unique instrument which assesses the presence of DSM-III-R personality disorders through a self report format. In spite of the limitations detected in the English version of the instrument, it has a wide distribution in psychiatric literature, because of its easy and economic application. The aim of this study is to translate into Spanish and validate the PDQ-R with the reference of a structured clinical interview for personality disorders. Methods. Thirty subjects with a clinical diagnosis of personality disorders were recruited from the external and hospitalization services of the Mexican Institute of Psychiatry. The personality disorder diagnosis was confirmed through Spitzer's structured clinical diagnostic interview for DSM-III-R (SCID-II). Healthy controls (30) were recruited from a community sample which also received the SCID-II to assess the presence of personality disorders. All cases and controls completed the PDQ-R format. Results. An overall diagnostic sensitivity and specificity of 90 % was found for the diagnosis of at least 1 personality disorder with a cut-off point of 55 points of the PDQ-R. The instrument showed an adequate diagnostic validity for cluster C and cluster B personality diagnosis and poor validity for cluster C. In general, and congruent with the English version, the PDQ-R showed generally acceptable values of negative predictive value (0.76 to 1.00) and generally poor positive predictive values (0.05 to 0.72). Conclusion. The Spanish version of the PDQ-R behaves similarly to the English version, with a differential validity between personality cluster and good negative predictive values. The instrument may be used for research in Spanish-speaking populations, as long as its limitations are accounted for in future research designs.