Your depression might be the result of your genes associated with anxiety, worry and low mood, researchers say, that the findings may shed light on the causes of depression, and could help improve diagnosis and treatment.
The study, DNA analysis of over 300,000 people, revealed 116 gene variations linked to neuroticism -- characterised by feelings of anxiety, worry and guilt.
The same genes associated with neuroticism had some overlap with genes linked to a susceptibility to depression and some other psychiatric conditions.
More than half of the genetic variations associated with neuroticism are expressed in the brain, the researchers said.
"For millennia it has been recognised that people have a greater or lesser tendency to feel low, worry, and experience other negative emotions. We knew that a part of the explanation is genetic differences between people, but it's been a mystery which genes are involved," said Michelle Luciano, from the University of Edinburgh.
"These new results make a substantial contribution to solving that mystery by pointing to many specific places in the genome that are linked with neuroticism," Luciano added.
For the study, published in the journal Nature Genetics, the team analysed genetic information from a group of people aged from 39 to 73, whose levels of neuroticism had been measured by a personality questionnaire.
The results promise paths to understand the mechanisms whereby some people become depressed, and of broader human differences in happiness. They are a resource for those seeking treatments for depression, the researchers said.