When people in eight countries that have almost half the world's population were asked to choose the greatest challenges facing their country, 37 per cent of Australians named global warming compared with an overall average of 25 per cent and just 18 per cent of Americans and 20 per cent of Britons.

An even more eye-catching difference between Australia and the other nations was its concern about mental health issues. About 35 per cent of Australians named mental health as one of their country's two or three greatest challenges, in contrast to the international average of just 10 per cent, with the second-most worried country on that issue being China on 15 per cent.

The findings may suggest that public awareness campaigns about mental health have been successful in Australia but they also carry a potent warning for politicians about the unusual level of concern among voters on climate change.

One intriguing pattern in the eight-nation survey by London's King's College was that the fears and concerns of Australians were in most cases closer to those of Chinese respondents than to those of their traditional "cousins" and allies in the US and Britain or any of the other countries surveyed: India, Brazil, South Africa and Saudi Arabia.

The survey of 7000 people was conducted online and so it captured the views of only "elite" Chinese respondents who had access to the internet. However, it found that those relatively wealthy and educated Chinese had much in common with Australians on the four issues rated most highly by Australians: the economy (named by 44 per cent of Australians), global warming, mental health and the ageing of the population (31 per cent).

The economy was the most commonly named problem in all three developed countries and was cited by 82 per cent of Americans and 74 per cent of Britons.

It provoked nowhere near the same level of anxiety in more buoyant Australia, where perceptions were more in line with China, 30 per cent of whose respondents listed it as one of their country's top challenges.

Similarly, global warming was named as a top concern by only one in five Americans or Britons but the two countries that rated it most highly were Australia (37 per cent) and China (30 per cent).

The two countries most worried about mental health problems were Australia and China (15 per cent), compared with just 8 per cent of Americans and 11 per cent of Britons.

China (35 per cent) and Australia were again the two top countries naming the ageing population as a great challenge, ahead of 7 per cent in the US and 20 per cent in Britain.

War and terrorism were cited by 46 per cent of Americans and 27 per cent of Britons as among their country's great challenges but the issues were seen in the same way by just 16 per cent of Australians and 11 per cent of Chinese.

Australians also led the ranking in being concerned about cancer, as well as about global warming and mental health.

Poverty was the highest ranking concern for South Africa (70 per cent), Brazil (61 per cent), Saudi Arabia (46 per cent) and India (45 per cent) while the two nationalities that cited it least often as a concern for their own country were Australians (19 per cent) and Chinese (23 per cent).

King's College organised the research to draw attention to its efforts to find solutions for many of the problems raised by the survey, including a major fund-raising effort now underway with a heavy focus on mental health and cancer.

Best source for generic drugs for anxiety, depression and other mental disorders at http://www.budgetonlinepharmacy.com/Anti-Depressants/c30/index.html