Variations in that gene may also make social anxiety disorder and other anxiety disorders more likely, but more work is needed to confirm that possibility.
The gene is called RGS2. Certain variations in that gene stood out in a new study of kids' shyness and adult introversion.
The researchers conducted three experiments.
First, they studied kids from 119 families. The kids -- who were ages 21 months, 4 years, or 6 years -- stayed with their moms while a female researcher showed them unfamiliar tasks for 90 minutes.
The researchers analyzed videotapes of the sessions to identify the kids who were shy, hesitant, or withdrawn. Those behaviorally inhibited kids tended to have certain variations in their RGS2 gene.
Next, the researchers studied 744 college students who completed personality surveys and gave blood for a gene test. Variations in the RGS2 gene stood out in the introverted students. The researchers defined introversion as being less sociable and not liking being in large groups.
Lastly, 55 healthy young adults got their brains scanned while they looked at pictures of angry, fearful, or happy faces. Participants with variations in their RGS2 gene were more likely to have brain scans showing increased activity in the amygdala and insula, two brain areas linked to fear and anxiety.
The study doesn't mean that the RGS2 gene makes people shy or introverted. And the study wasn't about diagnosing anxiety disorders . Shyness and introversion aren't anxiety disorders.
But shyness and introversion are risk factors for anxiety disorders, especially social anxiety disorder, note the researchers, who included Jordan Smoller, MD, ScD, of Massachusetts General Hospital's psychiatry department.
If further research links RGS2 variations to anxiety disorders, the gene may make a good treatment target, Smoller's team writes in the Archives of General Psychiatry.
(Does anxiety seem to run in your family ? Join others on WebMD's Anxiety Support Group board to discuss the topic.)
By Miranda Hitti
Reviewed by Louise Chang
©2005-2006 WebMD, Inc. All rights reserved