Screening Accuracy of Reduced Scales PHQ and GAD in Young People Living in Deprived Urban Areas in Bogotá, Buenos Aires and Lima

Objective To evaluate the sensitivity and specificity of the PHQ-3, PHQ-2, GAD-3, and GAD-2 in young people from deprived urban areas in Bogotá, Buenos Aires, and Lima for early depression and anxiety detection. Methods Adolescents (15–16 years) and young adults (20–24 years) from low-income neighborhoods in these cities were recruited. Sensitivity, specificity, and accuracy were assessed at different cut-off points. A ROC curve analysis was performed, obtaining the AUC with 95% CI using PHQ-8 and GAD-7 (cut-off ≥10) as references. The Youden index identified optimal cut-off points. Results Two thousand four hundred two individuals completed PHQ-8 and GAD-7; 45.0% were adolescents, 55.0% young adults. Depression symptoms were present in 53.0% and anxiety in 40.9%. AUC values were 0.96 (PHQ-3) and 0.91 (PHQ-2). Optimal cut-offs: PHQ-3 ≥4 (sensitivity 91%, specificity 87%), PHQ-2 ≥3 (sensitivity 79%, specificity 90%), GAD-3 ≥4 (sensitivity 94%, specificity 78%), and GAD-2 ≥3 (sensitivity 76%, specificity 91%). Conclusions PHQ-3 and GAD-3 scales demonstrate acceptable discriminative ability for screening depression and anxiety in young people living in deprived urban areas of the studied cities. Then, their three-item format allows for symptom screening with a shorter response time.