Scientists have for the first time established a genetic cause for depression narrowing it down to a specific chromosone.
The discovery was made by an international team of researchers led by King's College London who studied 800 families where two or more members had severe depression. They found clear evidence that chromosome 3p25-26 was strongly linked to the disorder. The paper is published in The American Journal of Psychiatry.
"This is a first step but it's a big step," said Professor Lefkos Middleton, one of the researchers. The next step will be to find the gene or genes responsible, understand their role and function and whether drugs can be used to correct it, he said.
Gerome Breen, lead author of the study and lecturer at King's College, London, the Institute of Psychiatry, said: "These findings are truly exciting as for the first time we have found a genetic locus for depression."
It was likely that the chromosomal region identified contributed only "a couple of per cent" to the risk of developing depression. But the discovery was significant because it was likely to lead to further genetic regions which could unlock the secrets of depression, which is forecast to become the disorder with the highest disease burden in the world by 2020.