A gene which regulates the movement of serotonin in the brain has been labeled the “happiness gene” by researchers from the London School of Economics and reported in the Journal of Human Genetics. This is the first study to demonstrate a direct link between an individual’s happiness and a specific genetic condition. The researchers measured people’s satisfaction with life to define happiness.

Behavioral economist Jan-Emmanuel De Neve, and team gathered genetic information from over 2,500 individuals in the National Longitudinal Study of Adolescent Health. They focused on which functional variant of the 5-HTT gene the participants possessed.

The 5-HTT gene has the operating code for serotonin transporters within our neuron cell walls. This gene has an allele (variation) which can be either short or long. The long allele works better, has more gene expression and more serotonin transporters in the cell membrane. We can have a genotype which may be short-short, long-long, short-long, or long-short – this we inherit from our parents.

The researchers asked participants this question: “How satisfied are you with your life as a whole?” They could answer: “Very satisfied, satisfied, dissatisfied, very dissatisfied, neither”. They then compared participants’ genotypes with their answers.

The researchers found that:

35% of those with the long-long version of the gene were very satisfied with their life

34% of those with the long-long version were satisfied with their life

19% of those with the short-short version were very satisfied/satisfied with their life

26% of those with the short-short version were dissatisfied with their life

20% of those with the long-long version were dissatisfied with their life

Those with one long allele had an 8.5% higher chance of being very satisfied compared to those with the short-short version

Those with two long alleles had a 17% higher chance of being very satisfied compared to those with the short-short version

Jan-Emmanuel De Neve said:

“It has long been suspected that this gene plays a role in mental health but this is the first study to show that it is instrumental in shaping our individual happiness levels. The results of our study suggest a strong link between happiness and this functional variation in the 5-HTT gene. Of course, our well-being isn’t determined by this one gene – other genes and especially experience throughout the course of life will continue to explain the majority of variation in individual happiness. But this finding helps to explain why we each have a unique baseline level of happiness and why some people tend to be naturally happier than others, and that’s in no small part due to our individual genetic make-up.”

Source: Journal of Human Genetics

Written by Christian Nordqvist