Study finds genetic link to optimism

2 March 2009. BY THE WELLCOME TRUST

Researchers from the University of Essex found that people with a specific genetic variation tended to seek out positive images and actively avoided negative ones.

The researchers say this may shed light on why some people are less likely to develop anxiety or depression than others.

In the study, nearly 100 individuals were asked to choose from two pictures at a time: one with positive or negative connotations, the other neutral. The researchers also examined the participants' DNA, looking specifically at a gene involved in transporting serotonin - the brain chemical associated with mood.

We inherit two copies of any gene. The study found that those who had two copies of a long version of the serotonin transporter gene selected positive images over the neutral ones. But in a choice between a negative and a neutral image, they actively avoided the negative ones. Those with one or two copies of a short version of the gene did not.

Such behaviour may help carriers of the long version avoid stressful events in life, protecting them from traumatic experiences. Previous studies have linked the short version of the gene with a higher risk of depression and suicide attempts.

"We have shown for the first time that a genetic variation is linked with the tendency to look on the bright side of life," said Professor Elaine Fox, Head of the Department of Psychology at the University of Essex and lead researcher on the study.

"This is a key mechanism underlying resilience to general life stress. The absence of this protection in the other forms of this genotype is linked with heightened susceptibility to anxiety and depression."

Image credit: Dianne Harris, Wellcome Images

Reference

Fox E, Ridgewell A, Ashwin C. Looking on the bright side: biased attention and the human serotonin transporter gene. Proceedings of the Royal Society B, published online before print 25 February 2009.