Scientists discover 17 genetic variations that raise risk of depression

Scientists have discovered 17 separate genetic variations that increase the risk of a person developing depression.

The findings, which came from analysing DNA data collected from more than 300,000 people, are the first genetics links to the disease found in people of European ancestry.

The scientists say the research will contribute to a better understanding of the disease and could eventually lead to new treatments. They also hope it will reduce the stigma that can accompany depression.

According to Nice, up to 10% of people seen by practitioners in primary care have clinical depression, with symptoms including a continuously low mood, low self-esteem, difficulties making decisions and lack of energy.

Both environmental and genetic factors are thought to be behind depression, with the interaction between the two also thought to be important. But with a large number of genetic variants each thought to make a tiny contribution to the risk of developing the condition, unravelling their identity has proved challenging.

Related: Antidepressant prescriptions in England double in a decade

While previous studies have turned up a couple of regions in the genome of Chinese women that might increase the risk of depression, the variants didn’t appear to play a role in depression for people of European ancestry.

But now researchers in the US say they have identified 17 genetic variations associated with the condition in Europeans, spread across 15 regions of the genome.

“It just underscores that depression really is a brain disease,” said Roy Perlis, the co-author of the research from Massachusetts general hospital. “Depression is about biology and I think that will be helpful for some people in reducing stigma and changing how we think about depression.”

To unpick possible genetic associations, the researchers examined data collected by the consumer genetic testing company 23andme. Of the 300,000 people studied, 75,607 self-reported a clinical diagnosis of depression or were receiving treatment for the condition.

By comparing the frequency of common genetic variations in the people with depression compared to those without, the scientists discovered two genomic regions associated with the condition, one of which has previously been linked to epilepsy and intellectual disability.

Further analysis, including 23andme data from another 150,000 individuals, as well as clinical data from a worldwide multi-institutional collaboration involving nearly 19,000 individuals, threw up more results, with scientists identifying 17 genetic variants in 15 genome regions associated with depression. The findings are published in the journal Nature Genetics.

While the genetic variants found are thought to contribute, at most, a few percent to the overall risk for depression, the results are valuable, said Perlis. “It is a very small proportion of risk, this is not the sort of finding that can be used to make a diagnostic test or predict depression. The reason this kind of genetics is important is it points us towards a biology of disease,” he said.

Understanding what the genes do and how they interact could lead to better treatments for depression, Perlis continued. “In general that would tend to make it less likely rather than more likely that we would find [genetic] associations,” he said, adding that the researchers found a strong link in the cohort between depression and other related conditions such as anxiety, obesity and sleeplessness. “These are the people who ultimately we would like to be able to develop other treatments for – not research participants, but people who get diagnosed with depression and treated for depression.”

Elisabeth Binder from the Max Planck Institute of Psychiatry in Germany, and who was not involved in the study, agrees. “With this paper alone we cannot explain very much about depression but it is the first really substantial and valid genetic hits and now we can go in and look at these hits, look at connected hits and really start to understand the disease,” she said.

But, says Binder, the new research doesn’t shed light on sub-groups of depression, while it is likely that there are many genetic variants associated with depression that have not yet been found. However, she believes the new results could help researchers probe how genetic and environmental risk factors are connected.

What’s more, she says, with each genetic variant thought to contribute only a minuscule increase in risk for the disorder, and huge sample sizes needed to spot them, the research highlights the value of data from genetics companies. “I think the beauty of this study is that they were using data from the company 23andme and thereby really boosted the sample sizes in numbers that were unachievable using other types of studies that were ongoing in the regular research community,” she said.

But Jonathan Flint, from the University of California in Los Angeles, warns that the use of data based on self-reports of diagnosis is problematic. Not only are many individuals with major depressive disorders likely to never have received a diagnosis, others might have been diagnosed who do not meet the criteria for the condition.

“What we might be identifying here is something much more to do with help-seeking behaviour than anything to do with a psychiatric illness,” he said.

Scientists discover 17 genetic variations that raise risk of depression

Clear variations between natural and non-natural food, research finds

Organic foods has a lot more of the antioxidant compounds linked to far better overall health and reduced levels of toxic metals and pesticides, in accordance to the most thorough scientific examination to date.

The global scientific group behind the new operate suggests that switching from regular to organic fruit and veggies could give the identical benefits as including one or two portions of the “5 a day” presently recommended.

The crew, led by Prof Carlo Leifert at the University of Newcastle, concludes that there are “statistically considerable, meaningful” differences, with a range of antioxidants becoming “considerably higher” – in between 19% and 69% – in organic food. It is the 1st review to demonstrate clear and wide-ranging differences in between organic and conventional fruits, vegetables and cereals.

The researchers say the increased levels of antioxidants are equivalent to “a single to two of the five portions of fruits and vegetables advisable to be consumed day-to-day and would as a result be considerable and meaningful in terms of human nutrition, if details linking these [compounds] to the well being positive aspects connected with enhanced fruit, vegetable and complete grain consumption is confirmed”.

The findings will bring to the boil a extended-simmering row above no matter whether people differences imply natural foods is greater for men and women, with one expert calling the perform sexed up.

Tom Sanders, a professor of nutrition at King’s College London, explained the study did display some differences. “But the question is are they inside natural variation? And are they nutritionally appropriate? I am not convinced.”

He stated Leifert’s operate had triggered controversy in the previous. “Leifert has had a lot of aggro with a good deal of people. He is oversexing [this report] a bit.” Sanders also noted that the investigation showed organic cereals have significantly less protein than standard crops.

The research was peer-reviewed and is published in a respected scientific journal, the British Journal of Nutrition. It was due to be released following week, but has presently appeared on numerous academic sites.

The final results are primarily based on an analysis of 343 preceding peer-reviewed scientific studies from all over the world – far more than ever prior to – which examine differences amongst natural and traditional fruit, greens and cereals.

“The crucially crucial point about this research is that it shatters the myth that how we farm does not have an effect on the quality of the meals we eat,” said Helen Browning, chief executive of Soil Association, which campaigns for natural farming.

Uk income of organic food, which is often significantly a lot more pricey than non-organic, are recovering soon after a slump throughout the financial crisis.

Plants produce numerous of their antioxidant compounds to battle back towards pest attacks, so the greater ranges in organic crops might result from their lack of safety by chemical sprays. But the scientists argue that other motives may be crucial, such as organic types being bred for toughness and not currently being overfed with artificial fertilisers.

Leifert and his colleagues conclude that a lot of antioxidants “have previously been linked to a lowered chance of continual diseases, like cardiovascular illnesses, neurodegenerative illnesses and specific cancers”. But they also note that no prolonged-term studies showing overall health rewards from a broad organic diet have however been performed.

One of the most striking results from the operate was the significantly greater amounts of cadmium, a toxic metal, in typical crops. They also discovered that pesticide residues have been located on standard crops 4 occasions much more typically than on organic foods. The research was funded by the European Union and an organic farming charity.

The analysis is certain to be criticised for a quantity of causes. The inclusion of so numerous studies in the evaluation could indicate poor-top quality operate skews the benefits, despite the fact that the staff did “sensitivity analyses” and identified that excluding weaker perform did not drastically adjust the outcome.

One more criticism is that the higher levels of cadmium and pesticides in typical generate had been even now nicely under regulatory limits. But the researchers argue that cadmium accumulates above time in the human body and that some people may possibly wish to avoid this, and that pesticide limits are set individually, not for the cocktail of chemicals employed on crops.

A further criticism is that the variations noticed may possibly outcome from distinct climate, soil varieties and crop varieties, and not from natural farming, though the researchers argue that combining many studies need to common out these other differences.

The best criticism, nonetheless, will be in excess of the tips of likely wellness advantages. The most recent major evaluation, which took in 223 studies in 2012, identified little evidence. “The published literature lacks robust proof that natural foods are drastically much more nutritious than typical foods,” it found.

This was also the conclusion of earlier, smaller sized research published in 2009 in a scientific journal and by the United kingdom Food Specifications Company (pdf), even though the latter deemed just eleven scientific studies. The 2012 review did note that eating organic foods might assist people keep away from pesticide residues.

Sanders told the Guardian he was not persuaded by the new perform. “You are not going to be much better nourished if you consume natural foods,” he mentioned. “What is most critical is what you consume, not whether or not it is natural or typical. It really is whether or not you consume fruit and veggies at all.

“People are acquiring into a lifestyle program. They get an assurance it is not being grown with chemical substances and is not grown by huge enterprise.”

He additional that organic farming did aid to address the considerable problem in the United kingdom of soil degradation and extra fertiliser polluting rivers.

Soil Association polling (pdf) demonstrates healthier eating (55%) and keeping away from chemical residues (53%) are crucial motives cited by consumers for buying organic create. But several also say care for the setting (44%) and animal welfare (31%) are crucial, as is taste (35%).

Browning mentioned: “This analysis backs up what individuals think about organic foods. In other nations there has long been much larger amounts of help and acceptance of the advantages of natural food and farming. We hope these findings will carry the United kingdom in line with the rest of Europe.”

Clear variations between natural and non-natural food, research finds