Childhood trauma may leave a lasting imprint not just on the psyche but also in the DNA. This news comes from McGill University and the Suicide Brain Bank, a Quebec-based organization that carried out autopsies on suicide victims who had been abused as kids. Across the board, their brains showed DNA modifications that made them particularly sensitive to stress. Although gene variations are primarily inherited at conception, the findings show that environmental impacts can also introduce them later on. “The idea that abuse changes how genes function opens a new window for behavioral and drug therapy,” says study leader and neuroscientist Patrick McGowan.
During periods of adversity, the brain triggers release of cortisol, a hormone responsible for the fight-or-flight response. Due to differential gene expression associated with stress, the brains of child-abuse victims had lower levels of glucocorticoid receptors, McGowan found. Cortisol normally binds to these receptors; with fewer of them present, there is more cortisol and less resilience to feelings of stress.
In his study, McGowan reviewed medical records and police reports and interviewed family members to determine whether a subject was abused early in life. He then examined the subjects’ brain tissues and found that among those who had been abused, glucocorticoid-receptor expression was reduced by 40 percent. “If we can identify how these changes occur, we can identify those at high risk and ultimately find ways to treat them,” McGowan says.