Question: Have any genes for depression been discovered?
Answer: Well, I can't say that there's specific genes. There are regions on chromosomes that are suggestive of where one might look for genes.
There's some indication that the serotonin gene is implicated in depression -- that's probably the strongest gene that we know about. But we're on the verge of knowing a lot.
In order to study the genetics of a complex disorder -- and depression's what we call a complex disorder which means that the environment as well as the genes interact -- in order to study that, you need very large samples of patients. And we are now are collecting those samples. And people have been very generous in donating their time and also their DNA to these studies. We have looked at now over 1,000 sib pairs, that's where there's depression in both the individual and their sibling. And we're on to now collecting the next 1,000. And there's similar studies going on in Europe.
And we hope to be able to put those together so that we will do what's called genome-wide association studies, and get a much better look, except we may need more than 2,000, we may need 10,000 samples. So, we are very actively pursuing this kind of research.