Closing the measurement gap for adolescent mental health: Validating the SDQ in Nigeria

<i>Background:</i> Adolescence is a critical period for the development of mental health disorders, making early identification during this time essential for enabling targeted interventions and preventing long-term adverse consequences. Globally, one in seven adolescents experiences poor mental health, including depression and anxiety, yet many countries, especially in sub-Saharan Africa, face a scarcity of mental healthcare provisions.<i>Method:</i> To aid early identification and intervention of adolescent mental health problems, this study assessed the psychometric properties of the Strengths and Difficulties Questionnaire (SDQ) in a representative sample of <i>n</i> = 2 178 <i>(n</i> = 1 366 female, aged 10-19 years, mean age = 14.758 years, SD = 1.902 years) in Nigeria. Further, we specifically examined the measure's factor structure and measurement invariance across demographic groups of sex, age, parental education, and parental marital status.<i>Results:</i> Our results demonstrated that the original five-factor model of the SDQ did not fit well for the Nigerian sample, consistent with previous studies in sub-Saharan Africa. A three-factor model previously proposed for Nigeria similarly did not achieve good model fit, necessitating further psychometric probing. We propose a modified five-factor model (releasing three items, 'I am restless', 'I get very angry', and 'I am usually on my own'), which showed excellent fit and full scalar measurement invariance across sex and age groups, supporting its utility in diverse demographic groups. Partial scalar invariance across parental marital status indicated that family dynamics may influence responses to certain items.<i>Conclusions:</i> These findings underscore the importance of refining the SDQ for use in sub-Saharan Africa and highlight the need for culturally appropriate tools to address adolescent mental health challenges across diverse settings.