Adverse Childhood Experiences and Adult Mental Health Across the Life Course: A Nationally Distributed Study in Nigeria

This study examines the cumulative effects of adverse childhood experiences on adult mental health outcomes across the life course in Nigeria, employing a nationally distributed retrospective cohort design across all six geopolitical zones. The Adverse Childhood Experiences framework, originally developed through Kaiser Permanente studies in the United States, has demonstrated remarkable predictive power for adult mental and physical health globally but has not been systematically tested with nationally representative samples in sub-Saharan Africa. This research recruited 2,100 adults aged 25 to 60 years through stratified community sampling in 12 states representing all geopolitical zones. Adverse childhood experiences were assessed using a culturally adapted 12-item inventory developed through prior qualitative piloting in Nigerian communities. Adult mental health outcomes included depression, anxiety, post-traumatic stress disorder, substance use, and subjective wellbeing. Dose-response analyses, survival analysis for disorder onset age, and moderated regression examined the cumulative and interactive effects. Results confirm a strong, graded dose-response relationship between adverse childhood experience scores and adult mental health burden across all zones, with four or more experiences associated with a five-fold increased odds of major depression. Unique adverse childhood experience profiles emerged across zones, with community violence and food insecurity featuring prominently in northern zones. Spiritual coping and social community belonging moderated adverse childhood experience effects, demonstrating indigenous protective mechanisms. Keywords: adverse childhood experiences, adult mental health, life course, Nigeria, dose-response.