Purpose: Depression is a highly prevalent, relatively underdiagnosed and undertreated comorbid condition in epilepsy. The purpose of this study was to determine the effect of using a validated self-reporting depression scale on the ability to detect depression in people with epilepsy receiving care in a busy clinical setting.
Methods: The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is a 6-item questionnaire validated to screen for depression in people with epilepsy. We performed a retrospective chart review of 192 consecutive patients who had completed the NDDI-E while receiving care at a seizure clinic in the largest public hospital in Houston, Texas. For comparison, charts of 192 consecutive patients receiving care immediately prior to the implementation of the NDDI-E in the same clinic were assessed.
Results: Fifty-five (28.6%) of patients screened positive for depression with the NDDI-E. They subsequently received a semi-structured psychiatric interview based on the DSM-IV model and 89% (n=49) were confirmed to have major depression. Use of the NDDI-E thus resulted in the detection of active depression in 25.5% (n=49) of the patients, whereas only 2.6% (n=5) of patients in the group not systematically screened were found to have active depression (p<0.0001). Thirty-two of the 49 (65%) patients with depression detected by screening were not previously diagnosed or treated. Multivariate analysis revealed that a history of depression, seizure frequency, and topiramate use were independent predictors of depression. Lamotrigine use was protective against depression.
Discussion: Use of the NDDI-E significantly improved the ability to detect depression in epilepsy patients in a busy clinical practice.