A genome-wide analysis of nearly 200,000 military veterans has identified six genetic variants linked to anxiety. Published in the American Journal of Psychiatry, this is the largest genome-wide association study (GWAS) to date, and has given insights into how people may be pre-disposed to anxiety disorders and provides further explanations for why anxiety and depression often coexist.

The Million Veteran Program is a compilation of health and genetic data on more than 800,000 U.S military veterans run by the U.S. Veterans Administration to research the way genes and lifestyle affect those veterans who have participated. Generalised anxiety disorder often manifests in veterans who have waged in war far from home. The genetic profiles of these veterans can give clues as to what genetic traits can affect the development of this disorder and can help to understand it in the population as a whole.

The genetic data of 199,611 veterans with a continuous trait for anxiety based on a diagnostic scale for Generalised Anxiety Disorder was used for the study. The data from the Million Veteran Program is very racially diverse and therefore, very valuable. Other similar large-scale studies have often used participants from a similar background, often with European ancestry.

This study found five genes in veterans of European descent and one gene in those of African American descent that may be associated with anxiety.

One gene found was MAD1L1, which has been linked to anxiety in other genome-wide association studies and to other psychiatric conditions such as schizophrenia and bipolar disorder. However, the function of this gene is not fully understood.

Another gene identified was connected to oestrogen. This was an interesting find as oestrogen is often associated with women, but 90% of the veteran cohort was male. It could help explain why women are more than twice as likely than men to suffer from anxiety disorders, but further investigation is necessary to fully understand this.

In veterans of African American descent, a gene associated with intestinal functions was found to be potentially linked to anxiety. This gene variant hasn’t been found to exist outside African populations

The results from genome-wide association studies like this one could be useful in determining someone’s susceptibility to anxiety early on and could possibly help in developing management techniques for those who are at high risk before symptoms even begin. Pharmaceutical research could also identify targets in genes to develop drugs that could help combat the disorder.