An Analysis of Measurement Invariance of the Patient Health Questionnaire-9 Between Indonesia, Germany, and the USA

The Patient Health Questionnaire-9 (PHQ-9) is a screening tool for assessing depressive symptomatology that has received widespread use. However, there is a scarcity of research on whether the instrument measures the same construct between high-income (HIC) and low- and middle-income countries (LMICs). Online surveys were utilized to assess samples across Indonesia, Germany, and the USA (<i>N</i> = 2350). Measurement Invariance (MI) was computed using multi-group confirmatory factor analyses. We found the general factor model to have a good fit and configural, metric, scalar, and residual MI across three countries. There were no significant differences in mean scores (Indonesia, <i>M</i> = 1.87, <i>SD</i> = 0.56; Germany, <i>M</i> = 1.90, <i>SD</i> = 0.65; USA, <i>M</i> = 1.90, <i>SD</i> = 0.75). These results highlight that depressive symptomatology is universal across distinct geographical regions, regardless of the population's income levels. Hence, this study further emphasizes the urgency of developing universal, accessible assessment and treatment for depression.