Genetic factors are estimated to account for about 35–50% of the variance in human happiness, and researchers have for the first time pinned at least part of this genetic influence down to a single gene, monoamine oxidase (MAOA). A team at the University of South Florida (USF) working with colleagues at NIH, Columbia University, and the New York State Psychiatric Institute has found that women who carry the low-expression MAOA gene (MAOA-L) are happier than those with high-MAOA expression.
Interestingly, reports USF’s Henian Chen, Ph.D., and colleagues, this genetic link doesn’t seem to hold true for men, perhaps because the higher levels of testosterone produced in post-pubescent males cancels out the potential benefits of low-MAOA expression. “Maybe men are happier before adolescence because their testosterone levels are lower,” Chen points out.
The team made their discovery by analyzing data from a population-based sample of 193 women and 152 men participating in the Children in the Community mental health study, which followed individuals for over 30 years. After controlling for a wide range of factors including age, gender, race, education, income, marital/employment status, and mental/physical health, the team found that women who carried one copy of the MAOA-L allele were were significantly happier than those who carry two copies of the high-expression MAOA allele, while women who carried two copies of the MAOA-L allele were happier still.
MAOA regulates levels of serotonin, dopamine, and other brain transmitters targeted by antidepressants, so while its involvement in mood per se wasn’t that shocking, the finding that low MAOA has beneficial effects was completely unexpected. “I was surprised by the result, because low expression of MAOA has been related to some negative outcomes like alcoholism, aggressiveness, and antisocial behaviour,” Dr. Chen admits. “It’s even called the warrior gene by some scientists, but at least for women, our study points to a brighter side of this gene.”
In fact, while women carrying MAOA-L did appear to experience higher rates of mood and anxiety disorders, they also reported greater overall life happiness than men. “This new finding may help us to explain the gender difference and provide more insight into the link between specific genes and human happiness,” Dr. Chen adds. The investigators say more research is now needed to identify other genetic factors that impact on happiness. “Certainly it could be argued that how well-being is enhanced deserves at least as much attention as how (mental) disorders arise.”
The reseachers report their results in Progress in Neuro-Psychopharmacology and Biological Psychiatry, in a paper titled "The MAOA gene predicts happiness in women."