New research appears to confirm a genetic link between depression and anxiety. 

The Australian study identified 509 genes that influence both depression and anxiety, confirming a genetic relationship between the mental health conditions.

It is the first study to identify so many genes that are shared between depression and anxiety.

Senior researcher and head of QIMR Berghofer’s Translational Neurogenomics Group, Professor Eske Derks, says depression and anxiety are the two most prevalent psychiatric disorders in the world, and often co-occur together in the same person.

“Not a lot has been known, until now, about the genetic causes of why people may suffer from depression and anxiety. Both disorders are highly comorbid conditions, with about three-quarters of people with an anxiety disorder also exhibiting symptoms of major depressive disorder,” Professor Derks said.

“We identified 674 genes associated with either depression or anxiety – and importantly about three quarters of those genes were shared.

“Our research provides new insights into the genetic architecture of depression and anxiety and the genes that link them.

“The better our understanding of the genetic basis of these psychiatric conditions, the more likely we are to be able to treat them.

“It’s been observed in the past that people who have both depression and anxiety have more severe symptoms, have the illnesses for longer and are more resistant to treatments. We hope this study will help identify existing drugs that might be re-purposed to better target the genetic basis of depression and anxiety.”

The team examined the genetic relationship between 28 individual symptoms related to depression and anxiety to understand how they overlapped.

The complex disorders are influenced by large numbers of genes, with each having a small individual effect, and while many genes are shared between anxiety and depression, the study also found genes that are specific to each disorder.

For example, some of the genes that are unique to depression were linked to higher levels of the fat triglyceride in the blood – a condition called hypertriglyceridemia.

“The link between those depression-specific genes and hypertriglyceridemia suggests there may be a metabolic component of depression that is not as strong in anxiety,” researcher Jackson Thorp said.

“Conversely, our results showed that some of the genes specific to anxiety were related to blood pressure, which is consistent with previous research that has shown a link between the disorder and hypertension.”

The study is accessible here.