Psychometric evaluation of the PHQ-9 in university students: Factorial validity and measurement equivalence across three African countries

With the rising rates of depression and suicidality among university students, accurate measures of depression have become an essential public health matter. The Patient Health Questionnaire-9 (PHQ-9) is one of the measures often used to estimate and compare group depression prevalence rates. In this study we examined the factor structure, measurement invariance (country and gender), and reliability of the PHQ-9 in a sample of university students (N = 1064; Mage = 22.67 yrs., SD = 5.17; 61% = Female) from three African countries (South Africa, Kenya, Ghana). Four alternative factor structures of the PHQ-9 (i.e., one-factor and three correlated two-factor models) were tested with confirmatory factor analysis. Results supported the two-factor model (somatic and non-somatic factors), and the measure was invariant across gender and the three African countries. The findings suggest that the PHQ-9 may be suitable for estimating and comparing depression prevalence across groups of African university students.