A Canadian study's analysis of brain tissue from adults who committed suicide, finding key genetic changes in those who had suffered abuse as a child, reports abuse in a child's formative years, permanently alters the structure of their brains.

Underpinning the impact of stress on early brain development, the Nature Neuroscience study found abuse in early childhood affects the production of a receptor known to be involved in stress responses, inhibiting the expression of a stress hormone-related gene (NR3C1).

Previous research has also shown the association of abuse in childhood with increased reaction to stressful circumstances. However, it is still unknown how exactly environmental factors interact with genes and contribute to depression, including other mental disorders in adulthood.

A research team led by McGill University, in Montreal, examining the glucocorticoid receptor gene responsible for controlling the response to stress of 24-suicide victims,
12 with a history of child abuse and 12 with none, found chemical changes that reduced gene activity in those who suffered child abuse, leading to fewer glucocorticoid receptors, with an abnormally heightened response to stress, in those thus affected.

The study suggests childhood experience when the brain is developing, has a long-term impact on how one responds to stressful situations, though Professor Michael Meaney, study leader says bio-chemical effects can also occur later on in life.

The study shows how the reduced expression of the gene leads to an increase in hypothalamic-pituitary-adrenal (HPA) response to stressful situations, which have previously been linked to an increased risk of suicide, mood disorders and also schizophrenia.

The research underscores that children should be raised in a stable and safe environment, helping them deal with stress in adulthood.