Being depressed is not an entirely environmentally acquired condition. In other words, some people are more pre-disposed to it than others because of the genes they have inherited. This is why depression has, for so long been known to have a family connection. Although this was noted by the very earliest psychotherapists, the proof of a genetic link in depressed patients was not established for some time. However, scientists have now singled out one gene in particular as being associated with the condition although there may be others that also play their part which are still unknown. The family gene in question is known as chromosome 3p25-26, and it has been found in hundreds of patients who have a history of depression in their family trees.