Psychometric analysis of the Psychiatric Diagnostic Screening Questionnaire (PDSQ) and determinants of psychopathology in two outpatient clinics in Navarre (Spain).

Background: The self-report Psychiatric Diagnostic Screening Questionnaire PDSQ is designed to screen Axis I psychiatric disorders. We aim to determine its psychometric properties in Spanish outpatients and assess its relationship with two interviews (for psychopathology and for personality disorders) and clinical/demographic variables.

Methodology: We administered the study questionnaire, the Mini International Neuropsychiatric Interview Plus (MINI-Plus), the Standardised Assessment of Personality Abbreviated Scale (SAPAS), and the List of Threatening Experiences Questionnaire (LTE-Q) to 375 patients at two public outpatient centres. Reliability of the study questionnaire was evaluated (Cronbach's alpha, ?) and known-group validity measured by comparing groups based on demographic and clinical variables (binary logistic regression analysis) and MINI-Plus diagnoses (Mann-Whitney U). The diagnostic accuracy of the study questionnaire score was analysed taking the MINI-Plus diagnoses as the gold standard (ROC analysis).

Results: Internal consistency was adequate across all PDSQ scales (? >0.7; mean ?=0.85). Known-group comparisons were satisfactory. Female and male patients showed higher prevalence of internalizing and externalizing diagnoses, respectively. Younger age, more life events and limitations, higher SAPAS scores, and lower economic levels were linked to a greater number of PDSQ diagnoses. Inter-group differences were found for all PDSQ scales based on the corresponding MINI-Plus diagnoses. Mean values of sensitivity, AUC, and negative predictive value were 88.7, 0.82, and 96.7, respectively.

Conclusions: When applied to a sample of Spanish outpatients, the PDSQ exhibits satisfactory psychometric properties and adequate relationships with the psychopathology and personality interviews, and clinical and demographic variables. The study questionnaire is suitable for assessing comorbidity and psychopathology dimensions.