Researchers at Brown University have discovered that a genetic alteration caused by stress during childhood can change a person's biological risk for psychiatric disorders in later life.
Their research, appearing in the journal PLoS ONE, may explain the recognized link between parental loss and childhood maltreatment, and disorders such as depression and anxiety.
To better understand the connection between childhood woes and later mental health issues, researcher Audrey Tyrka turned to the field of epigenetics. Epigenetics is the study of changes to the genome that do not alter the DNA sequence, but influence whether genes will be expressed, or "turned on," versus whether they will be silenced.
Knowing that the connection between childhood maltreatment and psychiatric disorders has been linked to the hormone system that coordinates biological stress responses, the researchers sought to identify the root cause at a genetic level.
The researchers looked at 99 healthy adults, some of whom had a history of parental loss or childhood maltreatment. DNA was extracted from each of the participants using a blood sample, then analyzed to identify epigenetic changes to the glucocorticoid receptor (the glucocorticoid receptor is an important regulator of the stress response).
The researchers found that adults with a history of childhood adversity had increased methylation of the glucocorticoid receptor gene, which is thought to change the way this gene is expressed on a long-term basis. They also found that greater methylation was linked to blunted cortisol responses to the hormone provocation test. "Our results suggest that exposure to stressful experiences during childhood may actually alter the programming of an individual's genome. This concept may have broad public health implications, as it could be a mechanism for the association of childhood trauma with poor health outcomes, including psychiatric disorders as well as medical conditions such as cardiovascular disease," said Tyrka.
In past studies of animals, researchers have identified drugs that can reverse methylation effects. "More research is needed to better understand the epigenetic mechanism behind this association," concluded Tyrka. "This line of research may allow us to better understand who is most at risk and why, and may allow for the development of treatments that could reverse epigenetic effects of childhood adversity."
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Source: Brown University