Researchers from Weill Cornell Medical College and the University of California, San Diego, have linked a genetic variation in the fatty acid amide hydrolase (FAAH) gene to anxiety during adolescence, as they report in the Proceedings of the National Academy of Sciences this week. FAAH, they note, affects endocannabinoid anandamide (AEA) levels, which, in turn, affects the frontolimbic circuitry that's also involved in anxiety disorders.
"We know there are so many different factors — biological, environmental, genetic — that all interact together," first author Dylan Gee from Cornell tells LiveScience. "The new study helps to understand how genetic variation can emerge at different stages of development."
Through imaging studies of three to 21-year olds, Gee and her colleagues found that the effects of a FAAH gene variant become apparent in the brain by about age 12, as anandamide levels decrease. Changes in anxiety-linked behavior occur in parallel.
In particular, people with the FAAH A385 allele exhibited increased connections between the frontal and limbic structures of their brains and reported lower levels of anxiety, the researchers report. Studies using mouse models confirmed these findings.
"The finding that FAAH C385A effects on frontolimbic circuitry and anxiety emerge during adolescence may prove valuable in enhancing personalized medicine for anxiety disorders, which are the most common psychiatric disorders during adolescence," Gee and her colleagues write in their paper.