Is your happiness connected? A new study delves into the genetics of happiness

Happiness is a positive emotional state that influences a variety of clinical outcomes, including depression.

Previous studies have shown that people have a baseline level of happiness that remains relatively stable. In fact, this baseline level of happiness is likely to remain unchanged, even after major positive or negative life events, such as winning the lottery or being in a serious car accident.

Recently Scientific reports study developed a new LDpred-inf polygenic score that measures happiness in general. This approach was used to determine whether an individual’s well-being depends on measures of happiness.

A study. Consistent Effects of Happiness Genetics on Lifespan and Ancestry Across Multiple Cohorts. Image credit: Ground Picture / Shutterstock.com

About the study

The UK Biobank study is the largest genome-wide study (GWAS) to date, involving more than 222,000 individuals. UK Biobank asked research participants: “Overall, how happy are you?” twice, once at the start of the study and again five years later.

A GWAS was performed at both time points, d and their results were combined to obtain polygenic happiness scores (PGS). In addition to the UK Biobank participants, two additional cohorts were also included in the analysis, including the Adolescent Brain Cognitive Development (ABCD) cohort and the National Longitudinal Study of Adolescent and Adult Health (Add Health).

Each group included specific age groups. To this end, the ABCD group included children aged nine and 11, the Add Health group included individuals aged 25 to 35, and the UK Biobank included individuals aged 40 to 70.

The current study assessed whether a genetic predisposition to general happiness levels is associated with differences in white matter integrity or key brain structures. The researchers also examined whether measures of happiness affect well-being across age groups.

Participants’ saliva samples were collected and genotyped. In addition, magnetic resonance imaging (MRI) of the participants’ brains was performed.

LDpred-inf polygenic scores for the general happiness measure were constructed based on the ABCD and Add Health groups. The link between genetic scores for happiness and brain structure was determined using ABCD and UK Biobank data.

Results of the study

LDpred PGS analyzes using the Add Health and ABCD cohorts showed that genetically, happiness was largely a consistent effect across an individual’s life span, from 12 to 73 years of age. This effect was consistent across multiple ancestral origins, except for non-white ancestry in the Add Health group.

Genetic predisposition to happiness affects an individual’s well-being. Well-being is associated with being confident, calm, focused and energetic. This genetic makeup also affects brain structure, which is linked to psychological and cognitive health.

MRI analyzes have shown that only certain areas of the brain are associated with genetic predispositions to happiness; However, this prevalence may be underestimated due to known bias in the MRI subsample.

In the ABCD cohort, several brain regions were found to be associated with a genetic load for happiness. These regions are present in the hedonic brain circuit, which includes the nucleus accumbens and ventral pallidum. Moreover, these regions are closely related to the regulation of pleasure and happiness.

Previous studies have shown that the putamen, caudate nucleus, and nucleus accumbens are associated with pleasure. The nucleus accumbens and bed nucleus of the stria terminalis also appear to contribute to feelings of happiness.

In the ABCD cohort, an association was observed between the white subsample and left ventricular pallidum volumes. A similar association with the nucleus was not observed in the ABCD cohort; However, a marginal association was identified in the UK Biobank analysis.

In the past, the frontal lobe of the brain has been associated with hedonic emotions. Similarly, the researchers in the current study confirmed that significant frontal lobe volume is associated with hedonic emotions.

Conclusions

The genetic basis of overall happiness appears to have consistent effects on measures of happiness and well-being across the lifespan, across multiple ancestral backgrounds, and across multiple brain structures.”

Current research suggests a genetic basis for happiness levels across age groups and ancestral backgrounds. Furthermore, a significant relationship between measures of happiness and well-being has been observed throughout an individual’s life.