Child abuse and neglect and mental health outcomes in adulthood by ethnicity: Findings from a 40-year longitudinal study in New Zealand/Aotearoa

Background: Longitudinal studies consistently report adverse long-term outcomes of childhood maltreatment. Little is known about the impact of childhood maltreatment on mental health among a marginalized population (New Zealand Ma over bar ori); therefore, we cannot assume the effects of maltreatment are the same across the population. Objective: Associations were examined between childhood sexual abuse (CSA), childhood physical punishment (CPP) and childhood neglect (CN) (<16 years) and mental health outcomes 18-40 years, by ethnicity (Ma over bar ori/non-Ma over bar ori).Participants and setting: Data from the Christchurch Health and Development Study, a study of a birth cohort of 1265 children born in Christchurch in 1977. By age 40, 17.8 % (n = 191) reported New Zealand Ma over bar ori ethnic identity; 82.2 % (n = 883) were non-Ma over bar ori.Methods: CSA, CPP (<16 years) were measured at 18, 21 years; CN was measured at 40 years. Major depression, anxiety disorder, suicidal ideation, alcohol abuse/dependence and cannabis abuse/dependence were measured at ages 21, 25, 30, 35 and 40 years. Childhood confounding variables controlled. Analyses were extended to include Ma over bar ori ethnicity.Results: After statistical adjustment, experience of severe childhood maltreatment increased odds of mental health problems 1.8-2.6x, compared to no maltreatment; the effects of maltreatment were similar for males and females. For Ma over bar ori, some higher rates of mental health problems were seen among those maltreated, no statistically significant associations were detected after Bonferroni correction (among severe maltreatment vs. no maltreatment). Limitations should be considered when interpreting results.Conclusions: Exposure to childhood maltreatment has long-term effects into middle-age. Further research employing culturally-sensitive approaches may help clarify Ma over bar ori childhood maltreatment outcomes.