Examining brief and ultra-brief anxiety and depression screening methods in a real-world epilepsy clinic sample

Objective: Recent epilepsy quality measure recommendations for depression and anxiety screening endorse ultra-brief screeners, the Patient Health Questionnaire-2 (PHQ-2) and Generalized Anxiety Disorder-2 (GAD-2). Thus, it is important to assess how symptom detection may be affected using ultra-brief screeners compared with slightly longer, well-validated instruments: Neurological Disorders Depression Inventory-Epilepsy (NDDI-E) and Generalized Anxiety Disorder-7 (GAD-7). The objective was to compare symptom detection by brief versus ultra-brief depression and anxiety screeners in a large real-world epilepsy clinic sample.

Methods: This was a prospective, cross-sectional assessment of consecutive patients in an adult tertiary epilepsy practice who completed the GAD-7 and NDDI-E with embedded ultra-brief scales (GAD-2; GAD-Single Item: GAD-SI; NDDI-E 2 item: NDDIE-2) on a tablet and had clinic staff administered ultra-brief PHQ-2 (yes/no version) documented in the medical record at the same visit. Prevalences of positive anxiety and depression screens were calculated for each instrument overall, and by epilepsy status. Concordance correlation coefficients (CCC) were calculated comparing the ultra-brief with brief anxiety and depression instruments, and receiver operating curves (ROC) were calculated using the longer instruments as alternative standards.

Results: Among N = 422 individuals the prevalence of positive anxiety screen by GAD-7 was 24% and positive depression screen by NDDI-E was 20%. Positive anxiety and depression screens were significantly less prevalent among seizure-free individuals than those with continued seizures. The verbally administered yes/no PHQ-2 had only 1 positive screen (0.2%). Other than poor concordance between the PHQ-2 and NDDI-E, the screener pairs had acceptable concordance (CCC 0.79 to 0.92). Areas under the ROC curves were acceptable for the NDDIE-2, GAD-2 and GAD-SI (0.96, 0.98, and 0.89, respectively).

Significance: In this sample, clinic staff interview-administered yes/no PHQ-2 had exceedingly low sensitivity compared with the NDDI-E self-reported on a tablet. Further investigation is warranted to assess if poor detection is due to characteristics of this PHQ-2 in epilepsy samples, or method of administration in this clinic. The other ultra-brief anxiety and depression instruments demonstrated good concordance with the longer, well-validated instruments and may be useful in clinical practice.