WEDNESDAY, Aug. 29, 2012 (HealthDay News) -- A "happy" gene that affects females but not males may explain why women are often happier than men, research suggests.
In the new study, researchers analyzed data from 193 women and 152 men who were assessed for happiness and underwent DNA testing as part of a long-term study of mental health.
The team focused on the "monoamine oxidase A" (MAOA) gene, which regulates an enzyme that breaks down brain neurotransmitters such as serotonin and dopamine, "feel-good" chemicals targeted by many antidepressants.
One version of the MAOA gene raises levels of monoamine, which allows larger amounts of these neurotransmitters to remain in the brain and boost mood.
The researchers found that women with the low-expression version of the MAOA gene were much happier than other women. Compared to women with no copies of the low-expression version, those with one copy scored higher on the happiness scale and those with two copies scored even higher.
A large number of men carried the low-expression version of the MAOA gene, but they were no happier than those without it, the investigators found.
The study was released online in advance of print publication in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry.
"This is the first happiness gene for women," lead author Dr. Henian Chen, an associate professor in the department of epidemiology and biostatistics in the College of Public Health, at University of South Florida, said in a university news release.
"I was surprised by the result, because low expression of MAOA has been related to some negative outcomes like alcoholism, aggressiveness and antisocial behavior. 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," Chen said.
Women have higher rates of mood and anxiety disorders, but tend to have greater overall life happiness than men, according to background information in the news release.
The reason for this is unclear but this "new finding may help us to explain the gender difference and provide more insight into the link between specific genes and human happiness," Chen said.
The reason for the gender difference found in this study may be partly due to the hormone testosterone, the study authors suggested. Men have much higher amounts of testosterone than women and the hormone may cancel out the happiness effect of the low-expression version of MAOA in men, the researchers said in the news release.
Mental Health America offers tips to create joy and satisfaction.