Psychometric properties of the GAD-7 (General Anxiety Disorder-7): a cross-sectional study of the Peruvian general population

Background: Anxiety disorders are among the main mental health problems worldwide and are considered one of the most disabling conditions. Therefore, it is essential to have measurement tools that can be used to screen for anxiety symptoms in the general population and thus identify potential cases of people with anxiety symptoms and provide them with timely care. Our aim was to evaluate the psychometric properties of the General Anxiety Disorder-7 scale (GAD-7) in the Peruvian population. Method: Our study was a cross-sectional study. The sample included people aged 12 to 65 years in Peru. Confirmatory factor analysis, analysis of measurement invariance, convergent validity with the Patient Health Questionnaire-9 (PHQ-9) and internal consistency analysis were performed. Results: In total, 4431 participants were included. The one-factor model showed the best fit (CFI = 0.994; TLI = 0.991; RMSEA = 0.068; WRMR = 1.567). The GAD-7 score showed measurement invariance between men and women and between age groups (adults vs. adolescents) (ΔCFI < 0.01). The internal consistency of the one-factor model was satisfactory (ω = 0.90, α = 0.93). The relationship between depressive symptoms (PHQ-9) and anxiety symptoms (GAD-7) presented a moderate correlation (r = 0.77). Conclusions: Our study concluded that the GAD-7 score shows evidence of validity and reliability for the one-factor model. Furthermore, because the GAD-7 score is invariant, comparisons can be made between groups (i.e., by sex and age group). Finally, we recommend the use of the GAD-7 for the general population in the Peruvian context.