Determination of prevalence of depression in an epilepsy clinic using a brief DSM-IV-based self-report questionnaire

Depression in epilepsy is common, underrecognized, and an indicator of quality of life. The Patient Health Questionnaire nine-item depression scale (PHQ-9) is a self-administered questionnaire based on Diagnostic and Statistical Manual, Fourth Edition (DSM-IV) criteria with high sensitivity and specificity for diagnosing depression. Using the PHQ-9, we determined that one-third of 263 patients seen in an epilepsy clinic had scores consistent with major depression. Seizure-free patients had lower depression scores than those with persistent seizures. Depression scores were not related to the number or type of antiepileptic drugs used. One-half of patients with scores consistent with major depression were not on antidepressant medication. The brevity of the PHQ-9 is conducive to routine screening of patients with epilepsy.