The present study examined the extent to which childhood socio-economic status (SES) could account for differences in adult psychosocial outcomes between Māori and non-Māori individuals in a birth cohort of more than 1000 individuals studied to age 30.

Data were gathered on three measures of childhood SES (family SES, family living standards, family income) and adult psychosocial outcomes including mental health, substance use, criminal offending, and education/welfare dependence outcomes, as part of a longitudinal study of a New Zealand birth cohort (the Christchurch Health and Development Study).

Those reporting Māori ethnicity had significantly (p < 0.0001) poorer scores on the three measures of childhood SES, with estimates of Cohen’s d indicating a moderate effect size. Māori cohort members also had significantly (p < 0.05) greater rates of adverse psychosocial outcomes in adulthood. Controlling for childhood SES reduced the magnitude of the ethnic differences in psychosocial outcomes, but did not fully explain the differences between Māori and non-Māori. Adjustment for childhood SES had the strongest effect on education/welfare dependence, but weaker effects on mental health, substance use, and criminal offending.

Improvements in SES among Māori in New Zealand may, to some extent, ameliorate the long standing disparities in psychosocial well-being between Māori and non-Māori. However, efforts to improve Māori well-being will require an approach that moves beyond a sole focus on rectifying socio-economic disadvantage.