The seat of anxiety in the brain is a small area called the ­amygdala.

Once it gets anxious it’s difficult to calm it down – and this led Ruby Wax, in her book Sane New World, to coin the phrase, “naughty little amygdala”. Because of this “naughtiness” anxiety is common.

One in four people are diagnosed with an anxiety disorder at least once in their lifetime. Severe psychological trauma can trigger genetic, biochemical and anatomical changes in the cells of the brain’s amygdala – the brain region implicated in stress-induced anxiety, leading to the onset of anxiety ­disorders, including panic attacks and post-traumatic stress disorder.

But now a gene in the brain that drives anxiety symptoms has been identified by an international team of scientists. Amazingly, modification of the gene will damp down anxiety levels, offering a novel drug target for anxiety disorders, say researchers at the universities of Bristol and Exeter.

This is important as the efficacy of currently available anti-anxiety drugs is low, with more than half of patients not getting better. One of the reasons for this limited success is poor ­understanding of how the brain changes when we’re anxious.

In this study, scientists got down ­to the nitty-gritty and identified the molecules in the brain that underpin anxiety. They focused on molecules known as miRNAs that regulate proteins controlling the amygdala.

Following acute stress, the team found an increased amount of one type of molecule called miR-483-5p in the amygdalae of mice. Importantly, the team then showed that miR-483-5p acts as a molecular brake that offsets stress-induced amygdala changes and brings relief from anxiety.

The discovery of a novel amygdala miR-483-5p pathway through which the brain regulates its response to stress is the first stepping stone towards the discovery of new, more potent and much-needed treatments for anxiety disorders. Dr Valentina Mosienko, one of the study’s lead authors at Bristol University, said: “Stress can trigger a number of neuro-psychiatric conditions.

“While low levels of stress are counter-balanced by the natural capacity of the brain to adjust, severe or prolonged traumatic experiences can overcome the protective mechanisms of stress resilience, leading to the development of pathological conditions such as depression or anxiety. These miRNAs are strategically poised to control complex neuro-psychiatric conditions such as anxiety.

“The miR-483-5p pathway offers potential for the development of anti-anxiety therapies for complex ­psychiatric conditions in humans.”