Anxiety disorders are the most common mental illness in the U.S. Currently, they affect 40 million adults age 18 and older, or 18.1% of the population every year.
Changing dispositional anxiety
Now, new research may be able to help with this overwhelming condition. A novel study has found that boosting a single molecule in the brain can change "dispositional anxiety." This refers to a condition where one tends to perceive many situations as threatening.
"There are millions of people worldwide who suffer from debilitating anxiety and depressive disorders," said Andrew Fox, an assistant professor in the UC Davis Department of Psychology and a researcher at the California National Primate Research Center. "These disorders are also some of the leading causes of disability and days lost to disability."
Since anxiety disorders often emerge in adolescence, the researchers studied preadolescent rhesus macaques. It was eight years ago when studying these primates that researchers got their first glimpse of molecular alterations in the dorsal amygdala, a brain region responsible for emotional responses.
"The authors speculated that altered processes in this region might underlie early-life anxiety. Since then, the research team sequenced RNA from the dorsal amygdala to identify molecules related to dispositional anxiety and dorsal amygdala function. They eventually narrowed the potential molecules and selected neurotrophin-3, a growth factor, for further study," said the study's press release.
Neurotrophin-3 in the dorsal amygdala
To test their theory, the researchers boosted levels of neurotrophin-3 in the dorsal amygdala of juvenile rhesus macaques. They then noticed a decrease in anxiety-related behaviors.
They further conducted brain imaging studies. What they found was that neurotrophin-3 changed activity throughout the distributed brain regions that are responsible for anxiety.
Fox hopes that this is only the beginning of his work and that other scientists will continue to build on his research. His team has identified a list of additional promising molecules that could be interesting for future investigation.
"We're only just beginning. Neurotrophin-3 is the first molecule that we've been able to show in a non-human primate to be causally related to anxiety. It's one of potentially many molecules that could have this affect. There could be hundreds or even thousands more," said Fox.
The study is published in the journal Biological Psychiatry.