Objective: The early detection of patients with comorbid mental illness is of high clinical importance in chronic somatic diseases. To identify cases, screening instruments are recommended. The study compared the discriminant validity of the Hospital Anxiety and Depression Scale (HADS) and the General Health Questionnaire (GHQ-12) to detect mental disorders in the most frequent chronic somatic diseases.
Methods: Five hundred sixty-nine patients with musculoskeletal, cardiovascular, and cancer diseases participated in the cross-sectional, two-stage survey. First, patients were assessed with the GHQ-12 and the HADS. Second, they were examined for DSM-IV mental disorders by clinical standardized interview (CIDI). Using CIDI diagnosis as a criterion, the validity of the instruments for the detection of any mental disorder as well as of depressive and anxiety disorders was analyzed with receiver-operating characteristics analyses.
Results: The HADS performed better in all analyses compared to the GHQ-12. Best screening results with the HADS total scale were achieved for depressive disorders with an area under the curve of 0.82, a sensitivity of 74%, a specificity of 80%, and a misclassification rate of 21% (cutoff point=18). The positive predictive value is best (44%) for the detection of any mental disorder, with a cutoff point of 17.
Conclusions: The HADS total scale can be recommended as a valid screening instrument for the detection of comorbid mental disorders in patients with chronic somatic diseases. The use of the single HADS subscales has no advantage for screening performance.