People living in affluent countries are more likely to suffer from post-traumatic stress disorder than those in poorer nations, according to the results of a study that have surprised researchers.

The scientists, from the Netherlands, Australia and London, say they appear to have uncovered a paradox. They expected to find that countries with higher vulnerability to tragic events – because of factors such as malnutrition, poor sanitation and low incomes – would experience higher levels of post-traumatic stress disorder (PTSD). Instead, they found that the highest levels were in countries that were far better off.

Their paper, published in the British Journal of Psychiatry, finds that Canada has the highest levels of PTSD, followed by the Netherlands, Australia, the US and New Zealand. The lowest levels were found in Nigeria, China and Romania.

The findings may have relevance to the response of people in Europe to the violent killings that have been taking place.

“PTSD has often been linked to something that violates your expectations,” said Prof Chris Brewin from University College London, one of the authors. “You thought you were living in a world which is basically safe, people are basically well disposed toward you, and something happens that completely turns those ideas upside down. It is thought that makes it really hard for people to get over these events.

“But if you’ve been brought up in a very different society, you may not have so many of these illusions to start with. You already see the world as a much more dangerous place and it may not be so surprising when something terrible happens.”

It was a paradox because it was very well established that individuals or groups – such as ethnic minorities – suffering from social, economic or educational disadvantage within any country were at higher risk of PTSD than their better-off neighbours, said Brewin.

“Everyone assumed that the citizens of countries with fewer economic advantages would similarly be at greater risk and you’d have higher rates of PTSD than in more developed countries. But the interesting thing is we found exactly the opposite is the case,” he added.



Countries where more traumatic events occurred, such as wars, natural disasters and accidental deaths, had higher rates across the board. “The very curious thing – and I think we’re the first people to identify this – is that countries which are less well economically resourced and generally have much smaller health services and poorer psychiatric services actually have lower rates [of PTSD] than countries like ours,” said Brewin.



The authors said it was not to do with better diagnosis or more treatments for PTSD in the wealthier countries. The data came from representative samples of the populations in all 24 surveyed countries, where people were randomly contacted and interviewed to establish the levels of PTSD.

“PTSD is quite a controversial disorder and some people have argued we just don’t measure it properly – it’s a western concept we’re trying to impose on people from different cultures,” said Brewin. “But, in fact, we know know that although there are minor cultural variations, basically people from all over the world show the same syndrome. So it’s probably not that.

“And when we looked at figures for depression we found the same pattern: countries with the greater resources had the higher rates of depression as well, and there is not really an argument about how to measure depression cross-culturally – that’s well accepted.”



The authors said their findings now needed to be replicated by other studies.