The study described below is one of the largest studies ever published looking at the genes involved in human behavior.
In the journal Nature, the international team describes how it analyzed genomic data from hundreds of thousands of people to find genetic variants associated with our feelings of well-being, depression, and neuroticism.
Here are some key points about the happiness gene. More detail and supporting information is in the main article.
- An estimated 350 million people suffer from depression, worldwide
- Current understanding of the role of genetics in character traits is patchy
- This most recent study has pinpointed gene variants associated with depressive traits and neuroticism
- Unpicking the individual role of genes and environment is challenging
The opposite of happy
Researchers have located genetic variants associated with subjective well-being - how happy a person thinks or feels about his or her life.
Depression is a debilitating condition that affects an incredible number of people, globally.
Characterized by continuous low mood, feelings of hopelessness and despair, and low self-esteem, depression is a major problem.
The World Health Organization (WHO) refers to depression as the "leading cause of disability worldwide" and refers to it as "a major contributor to the overall global burden of disease."
WHO estimate that 350 million people suffer from depression, worldwide.
The Centers for Disease Control and Prevention (CDC) estimate that 7.6 percent of Americans aged 12 or over experienced depression in any 2-week period between 2009-2012.
So, although the study of happiness might, at first glance, appear whimsical, it is easy to see how discoveries in this field might be useful elsewhere. Any investigation that can shed light on the causes and potential treatments of depression could benefit the entire globe.
To date, very little information is available about the specific roles of genes on character traits, previous research has been limited by the small number of participants. The current study looked to rectify this and delved into larger sections of data.
One of the researchers, Alexis Frazier-Wood, assistant professor of pediatrics and nutrition at Baylor College of Medicine, Houston, TX, says:
"We report that we found three genetic variants associated with subjective well-being - how happy a person thinks or feels about his or her life. We also found two genes harboring variants associated with depressive symptoms and 11 genes where variation was associated with neuroticism."
The team also found that the gene variants are mainly expressed in the central nervous system and adrenal or pancreas tissues.
Previous studies, particularly ones using the Netherlands Twin Register, have found that there is a genetic component to how individuals experience happiness.
For the study, the team carried out a meta-analysis - that is, they brought together genomic data from many other studies - and used advanced statistical tools to analyze the pooled data as if it came from one huge study of 298,000 people.
The analysis pinpointed three gene variants associated with feelings of well-being, two with depressive symptoms, and 11 with neuroticism.
Genes and predispositions
Previous studies have suggested that individual differences in happiness and well-being might be linked to genetic differences between people. There is increasing interest in the topic as growing evidence suggests well-being is a factor in both mental and physical health.
However, the researchers warn that genes are not the whole story when it comes to determining how people think and feel about their lives. They explain that the environment, and how it interacts with genes, is just as important.
But, studying the genes could help us start to understand why some people might be biologically predisposed to develop these symptoms, they note.
The researchers also hope the findings, which are available for follow-up research, will help to clarify the picture of what causes differences in happiness. They see this breakthrough discovery as just the beginning and believe the variants they have located are but a small fraction of what is waiting to be discovered.
"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. We expect that many variants will play a part.
The genetic overlap with depressive symptoms that we have found is also a breakthrough. This shows that research into happiness can also offer new insights into the causes of one of the greatest medical challenges of our time: depression."
Prof. Meike Bartels, VU University Amsterdam
The researchers have no plans to stop their search; they are set to continue their investigations into the genetic basis of what makes some humans happier than others. The earlier findings will act as a springboard for a deeper dive into human traits.
Of course, happiness is a worthy subject to study, but the findings from investigations such as these aim predominantly to uncover the genesis of happiness' opposite number - depression.
As one of the most prevalent, debilitating disorders in the developed world, any clues to the origins of depression must be investigated thoroughly. Genetic markers might eventually work as early warning signs, diagnostic tools, or even become the basis of medical interventions.