Variations in a fear-controlling brain circuit could be a factor in adolescent anxiety disorders.
The anxious adolescent brain. I’m Bob Hirshon and this is Science Update.
When both mice and people hit adolescence, they become more prone to anxiety. To learn why, Cornell neuroscientist Dylan Gee and her colleagues conducted brain scans of over 1,000 young people from age three to twenty, as well as mouse neurostudies. They focused on connections between the brain’s fear center, called the amygdala, and a brain circuit that helps us forget fearful memories and regulate emotion.
We discovered genetic variation that emerges during adolescence in this circuit, which we think is associated with anxiety.
In humans, that variation wasn’t expressed in the brain until the age of twelve, and correlated closely with self-reported anxiety levels. Gee says the work, which is reported in the Proceedings of the National Academy of Sciences, is one step toward a goal of more personalized medicine and new therapies for anxiety disorders. I’m Bob Hirshon, for AAAS, the science society.
Making Sense of the Research
For good or bad, adolescents have a reputation for being very moody creatures. Or, as some parents put it, they can go from being Dr. Jekyll to Mr. Hyde in three seconds flat!
For some teens, though, moodiness isn't the only thing they may struggle with. Many teens experience an increase in anxiety during their adolescence. Researchers have long wondered why this happens, and it seems that Dr. Gee and her colleagues may have found one factor that could contribute to this anxiety.
Medications used to treat anxiety in adolescents are mostly informed by studies of the adult brain. Of course, the trouble with this is that kids are not adults. So, Dr. Gee and her colleagues set out to use developmental neuroscience to create better therapies for teens. To do this, they studied a certain version of the FAAH gene, the gene that helps regulate the body's response to potentially harmful stimuli. Previous studies showed that adults with this version of the FAAH gene, known as FAAH C385A, exhibited less anxiety and slightly different brain connections—their prefrontal cortex was more tightly wired to deeper parts of the brain where emotional memories are stored.
In studying adolescents, Dr. Gee and her colleauges wanted to find out how and if the effects of that gene changed over time. They studied the data from 1,050 healthy participants, ages 3-21, including their genotype, psychological assessments, and brain scans. They found that those with the protective C385A version of the FAAH gene showed higher frontolimbic connectivity, which contributes to better emotional processing by the brain, and lower self-reported anxiety—but only after 12 years of age. In children younger than 12, the gene didn’t have noticeable anxiety effects. The researchers believe that this indicates that changes in gene activity over time may lead to anxiety disorders.
Dr. Gee and other researchers do caution, however, that anxiety is a complex disorder that can't be attributed to just one gene. The C385A version of the FAAH gene is just one of many that could lead to anxiety problems.
Now try and answer these questions:
- What is the problem with using medications meant for adults with adolescents?
- What version of the FAAH gene is Dr. Gee and her colleagues studying? Why?
- What did the researchers discover?
- Do the results of this study mean that the researchers have found the root cause of anxiety? Why or why not?
You can help your students gain more insight into what it means to be a teenager by having them listen to the Clumsy Kids Science Update, which takes a look at where some of that teenage clumsiness comes from, and Depression Prevention Training, which examines how researchers are working to try to prevent depression in teens.
You also can extend the ideas in this Science Update with these Science NetLinks resources.