Depression can not be predicted by a few genes: study

A team of US scientists says that no specific group of genes can predict the risk of depression, and efforts to treat the mental disorder by targeting a few "guilty spawners" are doomed to failure.

Researchers, who evaluated the genetic and survey data of 620,000 people, found that the 18 most-studied depression-prone genes are actually no more badociated than randomly selected genes.

Over the past 25 years, researchers have published hundreds of studies suggesting that a small set of particular genes or gene variants play an important role in increasing susceptibility to depression .

Such research has fueled the hope that clinicians could soon use genetic tests to simply identify people at risk, and that pharmaceutical companies could develop drugs to counteract some genetically-based culprits, said researchers in a statement.

According to the Colorado University team at Boulder in the United States, previous studies were incorrect – or "false positives" – and the scientific community would have to abandon what are called "hypotheses." candidate genes ".

"This study confirms that efforts to find a single gene or a handful of genes that determine depression are doomed to failure," said Richard Border, a graduate student at the University of Colorado at Boulder. .

"We are not saying that depression is not hereditary at all. That's what we say is that depression is influenced by many variations and that each of them has a tiny effect, "said Matthew Keller, badociate professor at the University. from Colorado Boulder.

For the study, published in the American Journal of Psychiatry, researchers looked at 18 genes that appeared at least 10 times in studies focused on depression.

Among them was a gene called SLC6A4, involved in the transport of neurochemical serotonin. Research dating back 20 years suggests that people with some "short" version of the gene run a significantly greater risk of depression, especially when they are exposed to early trauma.

The researchers also examined the genes involved in the production of brain-derived neurotrophic factor (BDNF), a protein involved in the formation of nerves, and the neurotransmitter dopamine.

Using genetic data and surveys collected from individuals via the British Biobank 23andMe and the Consortium of Psychiatric Genomics, they sought to determine if any of these genes, or gene variants, was badociated with depression alone, or badociated with an environmental factor such as childhood trauma or socio-economic diversity.

"We found that, as a whole, these candidate genes are no more related to depression than any random gene," Keller said.

Keller said that in the field of genetics, scientists have known for years that hypotheses about candidate genes were skewed.

However, hopeful researchers in other areas, including psychology, have continued to publish studies – often based on smaller samples – that have maintained the idea of 39, a small set of "genes of depression".

"It's like in" The Emporter does not wear clothes. "I hope it's the last nail of the coffin for this kind of study," Keller said. .