Nature Neurosci. 12, 342–348 (2009)

Childhood abuse may leave its mark on DNA in ways that have an effect on stress responses decades later.

Previous research has shown that rat pups reared by inattentive mothers accumulate more methyl groups on a region of DNA that regulates the expression of a receptor for glucocorticoid hormones. As a result, fewer receptors are made, potentially enhancing the animal's response to stress.

Now Michael Meaney of McGill University in Montreal, Canada, and his colleagues have tested brain samples from people who committed suicide, and found that those with a history of childhood abuse had a similar methylation pattern to the neglected rat pups. They also had fewer than average glucocorticoid receptors. These measures did not differ between people with no history of abuse who killed themselves and unabused people who died by other means.