Discriminative validity of the Stroop Test Çapa Version for executive function deficits in bipolar disorder

Abstract

Objective: Cognitive impairment is a well-recognized feature of bipolar disorder and has been investigated as a potential endophenotypic marker. The Stroop test is a widely used measure of executive functions, particularly response inhibition and cognitive set shifting. In this study, we aimed to evaluate the Stroop Test Çapa Version by assessing its sensitivity and specificity in detecting executive function impairment in individuals with bipolar disorder during euthymia. Method: In this retrospective study, 156 euthymic individuals with bipolar disorder type I and 125 healthy controls were included. Receiver Operating Characteristic (ROC) analyses were conducted separately for the completion times of the Stroop A, B, and C subtests, as well as Stroop D, calculated as the difference in reaction time between Stroop C and Stroop B. Optimal, diagnostic, and screening cut-off points were identified for each score type, along with their corresponding sensitivity, specificity, and positive and negative predictive values. Results: Participants with bipolar disorder required significantly more time to complete all Stroop subtests compared to healthy controls (p < 0.007 for all comparisons). Among the subtests, Stroop C demonstrated the highest discriminative ability (AUC = 0.671; p < 0.0001), followed by Stroop A (AUC = 0.659; p < 0.0001), Stroop D (AUC = 0.649; p < 0.0001), and Stroop B (AUC = 0.606; p = 0.0019). Discussion: Our findings indicate that the Stroop Test Çapa Version, when used alone, does not yield high sensitivity or specificity in identifying bipolar disorder. Therefore, it should be integrated with other neuropsychological assessments to enhance the clinical and cognitive evaluation of individuals with bipolar disorder.