Researchers at the National Institute of Mental Health believe they may have located a gene that triggers anxiety and depression.

The study, led by Dr. Daniel R. Weinberger, director of the Genes, Cognition and Psychosis Program, revealed that subjects with a shorter version of the 5-HTT gene, a gene responsible for serotonin transport, seem to have different brain circuitry and response to negative stimuli.

An inherited trait, people with longer versions of the gene were found to be less susceptible to stressors, and this, though further testing is required, is a possible link to understanding how people cope with life.

Though environmental factors play a part as well, serotonin production that is too low is widely known to cause depression. Too much can cause mania.

During the study, 114 people were given brain scans while viewing a series of pictures depicting people with angry or fearful faces. With the brain’s fear circuitry available to view, it became apparent that people with the shorter version of the gene have a lesser ability to extinguish fearful reactions.

"The problem is not the alarm clock, but the button you push to stop the alarm," Weinberger said.
“[It] isn't that you're fearful, it's that you can't stop being fearful, you can't turn it off."
The findings appear in the May 8 online issue of Nature Neuroscience.