According to a new study, published in the Journal of Happiness Studies, people who rate themselves as the happiest are more likely to share a certain gene. Researchers claim that this holds true for countries as far apart as Ghana and Colombia, yet to boil a nation's emotional state down to a single section of our DNA seems highly simplistic, to say the least.

For the study, researchers used data from the World Values Survey (WVS) gathered between 2000 and 2014. The WVS is a global research project itself, looking into peoples’ values and beliefs, and how they change over time and in response to what. From this, they figured out the average percentage of people who reported to be “very happy” from countries around the world, and then looked at climatic data, prevalence of disease, World Bank economic data, and population genetics. According to the researchers, they found a “strong correlation” between the happiness of a nation and the prevalence of a particular variant of the fatty acid amide hydrolase, or “FAAH,” gene.

This, they say, prevents the breakdown of a particular chemical, anandamide, known to enhance “sensory pleasure” while helping to “reduce pain.” Those countries that have populations with the highest proportion of the gene variant also report themselves to be the happiest. These countries are widely distributed around the world, from Ghana and Nigeria in West Africa, to Mexico and Colombia in Latin America, to Sweden in Northern Europe. At the other end of the scale were Middle Eastern countries such as Jordan and Iraq, and the East Asian nations of China and Thailand.

^{A graph showing the apparent relationship between the FAAH gene variant and happiness. Minkov and Harris Bond, 2016.} 

To attempt to boil down something so subjective and variable to a single gene is a vast oversimplification. Even attributes you might think would be quite straightforward genetically speaking, such as height, are thought to be influenced by many different genes, so to suggest that something as complex as happiness might be down to one seems unlikely. There are many confounding factors that could be influencing whether or not a person in a certain country during a certain time reports themselves as being happy or not.

Even the researchers themselves admit that there are quite a few limitations to the study. Even though those in Russia and Eastern Europe had a high prevalence of the gene within their population, their reported happiness was still very low.

They say that economic wealth, politics, and disease did not significantly influence a nation's happiness, yet then go on to state that politics and economics did cause “fluctuations” in how satisfied the countries were. They even use an example of how happiness in Rwanda has been steadily increasing since the 1994 genocide. Presumably that isn’t to do with an increase in the FAAH gene within the population.  

Perhaps unsurprisingly, this isn’t even the first time that researchers have claimed to have found a “happiness gene.” An earlier study from 2011, however, puts it down to a different section of one's DNA, this time a gene called 5-HTT. If you have two copies of this, the researchers claimed, you’re twice as likely to say you’re satisfied with your life.  

As always, things are much more complex than they may seem.