Background: Lack of coordination between screening studies for common mental disorders in primary care and community epidemiological samples impedes progress in clinical epidemiology. Short screening scales based on the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI), the diagnostic interview used in community epidemiological surveys throughout the world, were developed to address this problem.
Method: Expert reviews and cognitive interviews generated CIDI screening scale (CIDI-SC) item pools for 30-day DSM-IV-TR major depressive episode (MDE), generalized anxiety disorder (GAD), panic disorder (PD) and bipolar disorder (BPD). These items were administered to 3058 unselected patients in 29 US primary care offices. Blinded SCID clinical reinterviews were administered to 206 of these patients, oversampling screened positives.
Results: Stepwise regression selected optimal screening items to predict clinical diagnoses. Excellent concordance [area under the receiver operating characteristic curve (AUC)] was found between continuous CIDI-SC and DSM-IV/SCID diagnoses of 30-day MDE (0.93), GAD (0.88), PD (0.90) and BPD (0.97), with only 9-38 questions needed to administer all scales. CIDI-SC versus SCID prevalence differences are insignificant at the optimal CIDI-SC diagnostic thresholds (χ2 1 = 0.0-2.9, p = 0.09-0.94). Individual-level diagnostic concordance at these thresholds is substantial (AUC 0.81-0.86, sensitivity 68.0-80.2%, specificity 90.1-98.8%). Likelihood ratio positive (LR+) exceeds 10 and LR- is 0.1 or less at informative thresholds for all diagnoses.
Conclusions: CIDI-SC operating characteristics are equivalent (MDE, GAD) or superior (PD, BPD) to those of the best alternative screening scales. CIDI-SC results can be compared directly to general population CIDI survey results or used to target and streamline second-stage CIDIs.