Psychometric properties and diagnostic utility of the State–Trait Anxiety Inventory in epilepsy with and without comorbid anxiety disorder

Abstract Objective Anxiety disorders are frequent comorbid disorder in patients with epilepsy (PWEs). The availability of validated screening instruments to detect anxiety disorders in PWEs is limited. The aim of the present study was to validate State–Trait Anxiety Inventory (STAI) in adult PWEs for the detection of anxiety disorders. Methods A total of 96 outpatients with epilepsy completed the self-report symptom scale and were diagnosed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition Text Revision (DSM-IV-TR) Axis I disorders (SCID-I). The sensitivity, specificity, positive and negative predictive values, and receiver operating characteristic (ROC) curves were assessed to determine the optimal threshold scores for the State-Trait Anxiety Inventory State (STAI-S) and State-Trait Anxiety Inventory Trait (STAI-T) anxiety subscales. Results Receiver operating characteristic analyses for STAI-T showed area under the curve at 84.7%. For diagnoses of anxiety disorders, the STAI-T demonstrated the best psychometric properties for a cutoff score ≥ 52 with sensitivity of 81.3%, specificity of 77.5%, positive predictive value (PPV) of 41.9%, and negative predictive value (NPV) of 95.4%. Conclusions The STAI-T proved to be a valid and reliable psychometric instrument in terms of screening for anxiety disorders in PWEs. In the epilepsy setting, STAI-T maintains adequate sensitivity, acceptable specificity, and high NPV but low PPV for diagnosing anxiety disorders with an optimum cutoff score ≥ 52.