This finding was recently replicated, in some respects, suggesting there is something to it. However, there remains a major reason for scepticism. If genes are so important when combined with adverse environments, why are there huge fluctuations in the prevalence of most emotional problems, like depression and violence? Since it takes millennia for genetic change to occur in a population, genes could not be the cause of these variations. In Britain, violence against the person has increased 45-fold since 1950. Equally, there can be dramatic drops in the amount of violence that can have nothing to do with genes: rates of homicide in America have almost halved since 1993.
'Bit of both', nature-nurture exponents would argue that it just goes to show that dodgy genes only get expressed if environments activate them. But that could not explain such huge changes. Far more probable is that genetic vulnerability explains none of a 45-fold change in such a short period - that an awful lot of people with no genetic susceptibility are made, rather than born, violent or non-violent, depending on their society.
Even if it emerges that genes are always involved to some degree, one of the most striking implications of such studies is that emotionally benign environments are crucial: if you want the minimum of depression or violence, they make an overwhelming case for having a minimum of poor people and abusive parents, rather than societies making tiny minorities super-rich.
One wonders how socially benign Australia is these days between the mountain of personal debt and the impending industrial law changes. One also wonders how the Bush administration train wreck is going to rebound on the Man of Steel's drive to make us all feel relaxed and comfortable.