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Gene Variants Linked to Anxiety
> 3/4/2008 10:46:39 AM

Following a study in this month�s Archives of General Psychiatry, researchers from Massachusetts General Hospital may be a step closer to understanding how anxiety can be passed down through families. In a series of experiments involving RGS2, a gene that has been linked to anxious behavior in mice, they studied how RGS2 affects personality, behavior, and brain activity. Results indicate that variations in this gene are associated with anxious traits in humans and may increase the risk for anxiety disorders.

Mice missing the RGS2 gene exhibit anxious and fearful behavior, and the researchers examined the connection between this gene and anxiety using participants from a previous study that focused on children's reactions to unfamiliar situations. Behavioral inhibition in such a situation can indicate vulnerability to anxiety disorders. Expanding on that study, the researchers tested blood samples from the children of 119 families that had participated in the study and discovered nine variations in the RSG2 gene that were associated with behavioral inhibition in those children. In a second experiment, the researchers tested blood samples from over 700 college students who had been previously assessed for personality traits. Significantly, the variants of RSG2 associated with inhibited behavior in children were also more common in students who had been identified as introverted. Behavioral inhibition and introversion both involve fearful or avoidant behavior in social situations and are seen as risk factors for social anxiety disorder, the most common form of anxiety disorder.

The researchers then used brain imaging technology to examine how RSG2 alters activity in the brain. Using MRI scans, they observed the brain activity of a second group of college students. These 55 students had all been previously screened for anxiety and mood disorders. While being scanned, the students viewed images of faces expressing different emotions, a test that causes activity in the amygdala. Students with the particular variations in RSG2 had increased activity in the amygdala as well as in the insula, another brain region associated with anxiety.

Genetics play an integral role in the development of psychiatric disorders, and it is important to remember that environmental factors also influence behaviors and contribute to psychiatric conditions. This study furthers our understanding of the genetics underlying inhibited and introverted behavior, and future studies should continue exploring how these genetic factors combine with environmental stressors to increase risk for anxiety disorders. For individuals struggling with anxiety, more research on the subject brings the hope of new and effective treatments for their symptoms.

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