Background: The Psychiatric Diagnostic Screening Questionnaire (PDSQ) is a brief, psychometrically strong, self-report scale designed to screen for the most common DSM-IV Axis I disorders encountered in outpatient mental health settings. In the present report, we describe the diagnostic performance (sensitivity, specificity, and positive and negative predictive values) of the PDSQ in an outpatient setting.
Methods: Six hundred thirty psychiatric outpatients presenting for treatment were evaluated with the Structured Clinical Interview for DSM-IV after completing the PDSQ. Patients arrived approximately 20 minutes before the scheduled time of the appointment to complete the scale. Diagnostic raters were blind to responses on the scale.
Results: The PDSQ's subscales' diagnostic performance varied in a predictable manner according to the cutoff score-as the threshold for case identification increased, subscale sensitivity decreased and specificity increased. Mean subscale sensitivities of 80%, 85%, and 90% resulted in mean subscale specificities of 78%, 73%, and 66%, respectively, and negative predictive values of 95%, 96%, and 97%. Receiver operating curves were determined for each subscale and all areas under the curve were significant.
Conclusions: The PDSQ is a diagnostic aid designed to be used in clinical practice to facilitate the efficiency of conducting initial diagnostic evaluations. From a clinical perspective, it is most important that a diagnostic aid have good sensitivity, so that most cases are detected, and high negative predictive value, so that most noncases on the measure are indeed noncases. Our results indicate that most of the PDSQ subscales were able to achieve this goal.