Asking patients about their general level of functioning: Is IT worth IT for common mental disorders?

Functional disability (FD) is a diagnostic criterion for the psychiatric diagnosis of many mental disorders (e.g. generalized anxiety disorder (GAD); major depressive episode (MDE)). We aimed to assess the contribution of measuring FD to diagnosing GAD and MDE using clinical (Global Assessment of Functioning, GAF) and self-reported methods (Analog scale of functioning, ASF and World Health Organization Disability Assessment Schedule WHODAS 2.0). Patients seeking professional help for mood/anxiety symptoms (N=244) were evaluated. The MINI interview was used to determine the presence of common mental disorders. Symptoms were assessed with two short checklists. Logistic and hierarchical logistic models were used to determine the diagnostic accuracy and the added diagnostic value of FD assessment in detecting GAD and MDE. For GAD, FD alone had a diagnostic accuracy of 0.79 (GAF), 0.79 (ASF) and 0.78 (WHODAS) and for MDE of 0.83, 0.84 and 0.81, respectively. Self-reported measures of FD improved the diagnostic performance of the number of symptoms (4% AUC increase) for GAD, but not for MDE. If assessed before symptom evaluation, FD can discriminate well between patients with and without GAD/MDE. When assessed together with symptoms, self-reported methods improve GAD detection rates.