Scientists may have discovered the human "happiness" gene. The new findings could be huge when it comes to treating depression and to account for differences in neuroticism.

Previous research using information from the Netherlands Twin Register and other sources had shown that individual differences in happiness and well-being could be partially due to genetic differences between people. In other words, different people feel happiness and well-being differently. Policy makers, in particular, are increasingly focusing on well-being since studies suggest that it is a factor in mental and physical health.

The latest study is a large-scale effort that involved more than 298,000 people. In this study, researchers found three genetic variants for happiness. Not only that, but two variants could account for differences in symptoms of depression.

The genetic variants for happiness are mostly expressed in the central nervous system. However, they're also found in the adrenal glands and pancreatic system. These findings, in particular, show which areas that researchers should target moving forward.

"This study is both a milestone and a new beginning: A milestone because we are now certain that there is a genetic aspect to happiness and a new beginning because the three variants that we know are involved account for only a small fraction of the differences between human beings," said Meike Bartels, professor at VU Amsterdam and one of the researchers involved in the new study. "We expect that many variants will play a part."

The researchers believe that studying the variants they found will help them study the interplay between nature and nurture. More specifically, it will show the differences in the way in which people experience happiness.

"The genetic overlap with depressive symptoms that we have found is also a breakthrough," Bartels said. "This shows that research into happiness can offer new insights into the causes of one of the greatest medical challenges of our time: depression."

The findings could be huge when it comes to better understanding the symptoms of depression. Not only that, but it could also lead to new treatments.

The findings are published in the April 2016 edition of the journal Nature Genetics.