Background Previous studies document a mental health advantage in British Indian children, the causes of which are unknown.

Methods Our subjects were 13 836 White children and 361 Indian children aged 5–16 years in the British Child and Adolescent Mental Health Surveys. Mental health was assessed using the parent, teacher and child Strengths and Difficulties Questionnaires (SDQs), and multi-informant clinician-rated diagnoses. Multiple child, family, school and area factors were examined as possible mediators or confounders of ethnic differences.

Results Indian children had a large advantage for externalising problems/disorders, and no difference for internalising problems/disorders. This was observed across all outcomes, and psychometric analyses provided no suggestion of information bias. The Indian advantage for externalising problems was partly mediated by Indian children being more likely to live in two-parent families and less likely to have academic difficulties. Yet after adjusting for these and all other covariates, the unexplained Indian advantage only reduced by a quarter (from 1.08 to 0.71 parent SDQ points) and remained highly significant. This Indian advantage was largely confined to families of low socio-economic position.

Conclusion The Indian mental health advantage is real and is specific to externalising problems. Family type and academic abilities mediate part of the advantage, but most is not explained by major risk factors. Likewise unexplained is the absence in Indian children of a socio-economic gradient in mental health. Further investigation of the Indian advantage may yield insights into novel ways to promote child mental health and mental health equity in all ethnic groups.