Abstracts

Rationale: The Beck Depression Inventory – Second Edition (BDI-II) is a patient reported measure that is widely used to assess depressive symptoms in various populations, but has never been validated in people with epilepsy. The purpose of this study was to evaluate the psychometric properties of the BDI-II in people with epilepsy.Methods: Data from a multicenter, open label, observational study assessing the effect of lamotrigine on low-moderate depressive symptoms in people with epilepsy was used to confirm the reliability, validity, and responsiveness of the BDI-II. The BDI-II contains 21 items designed to measure the incidence and severity of depressive symptoms for the past 2 weeks on a 4-point ordinal scale where higher scores indicate greater symptomatology. Total scores range from 0 to 63 where 0 – 13 indicates minimal depression; 14 – 19 mild depression; 20 – 28 moderate depression; and 29 – 63 severe depression. BDI-II scores can also be summarized as two subscales – Somatic-Affective and Cognitive. In addition, patients completed a number of other measures, including the Cornell Dysthymia Rating Scale (CDRS), the Quality of Life in Epilepsy scale (QOLIE-31), the Profile of Mood States (POMS), and the Center for Epidemiologic Studies – Depression Scale (CES-D). Patients were required to have a CES-D score >10 upon study entry.Results: A total of 158 adults with epilepsy participated in the study. Approximately 84% of the sample was white, 65% were female, and the average age was 39 years. The internal consistency reliability of the BDI-II total score was excellent: 0.91 at baseline, 0.92 at Week 19, and 0.89 at Week 36. The item-to-total correlations for BDI-II total items ranged from 0.36 to 0.64. Confirmatory factor analysis results confirmed the two-dimensional BDI-II structure and supported the scoring of Somatic-Affective and Cognitive subscales, as well as a BDI-II total score. The BDI-II was strongly correlated with the CES-D at all time-points (P < 0.0001), with correlations ranging from 0.47 to 0.74 and increasing in size from baseline to Week 36. Guyatt’s statistics compared study participants with CES-D scores of 16 or greater at baseline and less than 16 at follow-up to those study participants without CES-D score change of this magnitude; these responsiveness statistics range from –0.46 to –0.84, moderate to large in size. A similar responsiveness analysis using scores from the CDRS yielded larger responsiveness statistics, ranging in size from –1.00 to –1.92.Conclusions: The BDI-II is a reliable, valid, and useful measure of depressive symptoms in patients with epilepsy. Additional work to define the minimal important difference will expand the clinical utility of the BDI-II for assessing change in depressive symptoms in this population. (This research was funded by GlaxoSmithKline.)