Major depression (MD) is an understated disease. It is present in any culture and worldwide. I saw with regard to this a research highlight in Genome Medicine by M.Rivera and P. McGuffin, who commented on the succes of a whole consortium whose members did a tremendous search for genes linked to Major Depression and found them.
I then went to the paper itself in Nature which is prepared and written by the Coverge Consortium from China, Oxford and VCU in Richmond, VA. Some 5300 people with the disease were sequenced and compared to some 5300 healthy controls. The researcher were pointed to two genes which were analyzed in detail and variants thereof proved to dispose for MD. These are SNPs close to the Sirtuin 1 and the LHPP genes both on chromosome 10.
SIRT1 is a stress-response and chromatin-silencing factor. It is an NAD(+)-dependent histone deacetylase involved in various nuclear events such as transcription, DNA replication, and DNA repair (citation from OMIN 604479). LHPP is the phospholysine phosphohistidine inorganic pyrophosphate phosphatase. This gene has already been implicated in MD: http://www.nature.com/mp/journal/v14/n6/full/mp20088a.html.
This is an intriguing story for those involved in the science of MD, but also for the persons concerned. If there is a gene or some gene responsible, one is not to blame personally. This is a good finding.