In this study, researchers used data from the 1999 and 2004 British Child and Adolescent Mental Health Surveys, which took a nationwide sample of 5-16 year olds living in England. The proportion of Indian children with any mental health disorder was 3.7%, the lowest of any major ethnic group and substantially lower than the 10.0% proportion in White children. This Indian mental health advantage was driven by Indian children having fewer behavioural problems (e.g. aggressive or antisocial behaviour) and fewer hyperactivity problems. This pattern was reported by parents, teachers and children alike, suggesting that it reflects a real difference and is not the result of chance or biased reporting.
Part of the Indian mental health advantage was explained by the fact that Indian children were more likely to live in two parent familes and had higher academic abilities. Most of the advantage, however, was not explained by the major known risk factors. In addition, Indian children did not show the strong socio-economic gradient in behavioural and hyperactivity problems which was observed in Whites.So why is this? The authors looked at the usual suspects and threw up their hands. There are other conceivable suspects. Maybe people from that region are genetically different in the parts of the brain that cause mental disorders. I doubt it. We don't know if Indians in India are the same, and I think we would have noticed if a couple of billion people had 1/3 as much mental illness as Europeans. Maybe not.
Another modestly plausible suspect is epigenetics. Maybe getting curry through mother's milk affects early myelination, or maybe the way Indian moms handle their infants affects their seratonin/dopamine balance.
I'd put my first (also exceedingly modest) bet on culture, possibly acting through epigenetics. If I had to guess (and it's part of the Blogger's Oath that I will guess with a strength of opinion inverse to my actual knowledge of the subject), I'd guess that something in White British culture that makes kids crazy is ameliorated by the way Indian moms treat their little kids. And it probably has something to do with brain development. Is that general enough?