A major new study which has identified 44 genetic risk factors for depression has the "potential to revitalise treatment", scientists have said.
The international study, co-led by King's College London, is the largest carried out into a genetic basis for depression and involved more than 200 scientists.
Seven data sets were combined, covering 130,000 sufferers.
Among the 44 genetic variants identified, 30 are newly discovered.
Previous studies have struggled to identify more than a handful. A significant number were linked to the targets of current antidepressant medications.
Researchers said that all humans carry some of the 44 risk factors, and that the genetic basis for depression is shared with other psychiatric disorders such as schizophrenia.
A higher body mass index is also linked to an increased risk of depression, the research found.
Around 14% of the global population is affected by depression and it is the biggest contributor to long-term disability worldwide.
Only about half of patients respond well to existing treatments.
"With this study, depression genetics has advanced to the forefront of genetic discovery," Dr Gerome Breen from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London said.
"The new genetic variants discovered have the potential to revitalise depression treatment by opening up avenues for the discovery of new and improved therapies."
Professor Cathryn Lewis, also from the IoPPN, said: "Depression is an incredibly common disorder that affects millions of people in the UK.
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"This study has shed a bright light on the genetic basis of depression, but it is only the first step.
"We need further research to uncover more of the genetic underpinnings, and to understand how genetics and environmental stressors work together to increase risk of depression."