Children who often see their parents arguing are at greater risk of depression, experts warn.
Teenagers who witnessed lots of arguments in early childhood were more likely to suffer from the illness than others, said a Cambridge University team.
"Violent arguments in front of the children contribute to the likelihood of depression," said Professor Barbara Sahakian, of the university's psychiatry department and co-author of the report.
"If you are staying together for the sake of the family, then fighting and arguing in front of the kids is not good. It would be better for them not to have that kind of environment."
The team identified a gene that made some children more sensitive to emotions and also more likely to develop depression. Researchers came up with a simple test, that can be carried out at school, to identify those with the gene, allowing youngsters to get help before they suffer with the disease.