A growing body of research suggests that early life experience changes the way genes respond to the world—and this can influence everything from the way people respond to stress to their risks for various diseases.
A new study–published in Nature Neuroscience and led by Chris Murgatroyd of the Max Planck Institute in Germany–illustrates how early stress affects brain receptors for a chemical called vasopressin, which is involved in father/child bonding and in other social connections.
In the study, baby rats were taken away from their mothers for three hours a day during the first 10 days of life, an experience that is stressful for infants. When the rats were later examined, their memories were impaired in some situations and their stress systems were overactive.
Researchers specifically explored the genes involved in making a receptor for vasopressin in a particular part of the brain. They found that early-life stress changed the way these genes were expressed, producing more receptors. These changes could be reversed by blocking the receptors later.
In rodents, vasopressin has been linked with pair bonding—male prairie voles that have more vasopressin receptors in “reward” regions of their brains are monogamous, while male montane voles, which have a different pattern of these receptors, are not. Vasopressin is also linked with aggression: when male prairie voles bond with their mates, higher vasopressin levels are connected with increased aggression towards strangers who try to enter their territory.
It’s not yet known how much of this is applicable to humans—but vasopressin-related drugs are being studied as possible treatments for psychiatric disorders involving anxiety and aggression that could be related to early life experience.
And this much is clear: severe stress during infancy and late pregnancy can have a range of long-lasting effects on a child. Though another recent study explored in USA Today looked at stress rates amongst older children, the findings are probably applicable to infants as well.
That study found that while parents believe their children aren’t particularly affected by their stress levels and aren’t undergoing much stress, children report otherwise. Though you shouldn’t stress about it, if you can better manage the way you cope with stress, you aren’t only helping yourself, but probably your kids, too.