David Dawson's Profile

Genes that predispose people to depression, though, also influence their risk of experiencing negative environmental events. In one study, women whose identical twin suffered from depression were significantly more likely to have been assaulted, lost a job, divorced, or had a serious illness or major financial problems than people whose fraternal twin was depressed. (It’s not known which genes are responsible for this effect.) These bad events did not occur because the women were depressed, as the correlations persisted even when women who were currently depressed were excluded from the study. Thus, genes can act on the same disorder by making people more sensitive to stressful environmental events and by making these events more likely to occur.