Genetic study may explain why childhood abuse can lead to depression, other mental health effects and suicide:

Canadian researchers found early childhood abuse can change the expression of a gene which is important for responding to stress. The study, by Professor Michael Meaney and colleagues at McGill University, (published online in Nature Neuroscience) suggests childhood abuse appears to permanently change a person's response to stress, possibly making them more susceptible to suicide.

The researchers studied the brains of 24 suicide victims. 12 had suffered severe childhood abuse, which included physical abuse, neglect or sexual contact, and 12 had not been abused.
They also studied the brains of 12 accident victims who had not been abused. Those who had been abused had lower levels of expression of the gene for the glucocorticoid receptor, which is critical for the stress response pathway.

Previous rat studies have shown that early childhood experiences can cause long-term genetic changes in the pathway, however this is the first evidence in humans. "Childhood adversity might alter the development of systems that regulate stress responses ... enhancing the effect of stress in adulthood and vulnerability for mood disorders," the researchers say.

1. Meaney et al. Epigenetic nature of the glucocorticoid receptor in human brain associates with child abuse. Nature Neuroscience, 2009; http://www.nature.com/neuro/journal/v12/n3/pdf/nn.2270.pdf

2. ABC News (2009, February 23), Stress, abuse damages childhood genes. Retrieved March 20, from http://www.abc.net.au/science/articles/2009/02/23/2498511.htm?site=science&topic=latest

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