The happiest countries and happiest U.S. states tend to have unusually high rates of suicide, a new research suggests.

The research from the UK’s University of Warwick, Hamilton College in New York and the Federal Reserve Bank of San Francisco uses U.S. and international data that included comparisons of a random sample of 1.3 million Americans, and another on suicide decisions among around 1 million Americans.

Canada, the United States, Iceland, Ireland and Switzerland, display relatively high happiness levels and yet also have high suicide rates. Nevertheless the researchers note that, because of variation in cultures and suicide-reporting conventions, such cross-country scatter plots are only suggestive.

To confirm the relationship between levels of happiness and rates of suicide within a geographical area, the researchers turned to two very large data sets covering a single country, the United States.

The scientific advantage of comparing happiness and suicide rates across U.S. states is that cultural background, national institutions, language and religion are relatively constant across a single country. While still not absolutely perfect, as the States are not identical, comparing the different areas of the country gave a much more homogeneous population to examine rather than a global sample of nations.

Comparing U.S. states in this way produced the same result. States with people who are generally more satisfied with their lives tended to have higher suicide rates than those with lower average levels of life satisfaction, the research suggests. For example, the raw data showed that Utah is ranked first in life-satisfaction, but has the 9th highest suicide rate. Meanwhile, New York was ranked 45th in life satisfaction, yet had the lowest suicide rate in the country.

The researchers believe the key explanation that may explain this counterintuitive link between happiness and suicide rates draws on ideas about the way that human beings rely on relative comparisons between each other.

University of Warwick researcher Professor Andrew Oswald said: “Discontented people in a happy place may feel particularly harshly treated by life. Those dark contrasts may in turn increase the risk of suicide. If humans are subject to mood swings, the lows of life may thus be most tolerable in an environment in which other humans are unhappy.”

This result is consistent with other research that shows that people judge their well-being in comparison to others around them, Professor Stephen Wu of Hamilton College said. These types of comparison effects have also been shown with regards to income, unemployment, crime, and obesity.