Perhaps there is a bit of truth to the stereotype about being fat and happy — new research finds that people who have a gene linked with obesity may have a slightly lower risk of depression.

People who had a version of a gene called the FTO gene were 8 percent less likely to have depression, researchers found. In 2007, scientists discovered this version of the FTO gene was a major contributor to genetic obesity among people of European descent.

The finding "suggests that the FTO gene may have a broader role than initially thought, with an effect on depression and other common psychiatric disorders," the researchers wrote in their study published today (Nov. 20) in the journal Molecular Psychiatry.

The researchers said the findings challenge the idea that obesity and depression are generally linked. Some have suggested that obese people become depressed because of their appearance and discrimination, while people with depression may become less active and change their eating habits to cope with their illness.

"The difference of 8 percent is modest, and it won't make a big difference in the day-to-day care of patients," study researcher David Meyre, associate professor in clinical epidemiology and biostatistics at McMaster University in Canada, said in a statement. "But, we have discovered a novel molecular basis for depression," Meyre said.

The researchers looked at data gathered on more than 17,000 people who participated in a genetics study between 2001 and 2003. About 3,200 of the participants had depression. The researchers further supported the link they found by analyzing data on genes of patients in three additional large international studies.

Still, further studies are needed to confirm the findings, they said.

Previous studies of families have suggested that 40 percent of the risk of depression comes from genetics, the researchers said. However, attempts to find specific genes associated with depression have not produced convincing evidence so far, according to the study.

This finding is important because about 9 percent of U.S. adults have depression at any given time, according to estimates from the Centers for Disease Control and Prevention.