Post a recent study on mice, researchers have realized that early life trauma and stress can result in behavioural problems.
Christopher Murgatroyd, a scientist from the Max Planck Institute of Psychiatry in Munich, Germany, who led the study, briefed that the stressed mice produced hormones that "changed" their genes, to affect their long-term behavioural "programme."
The researchers had to cause stress to newborn mice to observe the affect on them throughout their lives.
"We separated the pups from their mothers for three hours each day for ten days," the BBC News quoted Murgatroyd as saying.
He added: "It was a very mild stress and the animals were not affected at a nutritional level, but they would [have felt] abandoned."
It was found that those mice "abandoned" early on in their lives had become less able to cope with stressful situations and also had poorer memories.
Murgatroyd said that these results were because of "epigenetic changes", meaning the alteration in the DNA of some of the animals' genes.
Murgatroyd said: "This is a two-step mechanism."
He elaborated that the stressed baby mice produced high levels of stress hormones which "tweak" the DNA of a gene that codes for a specific stress hormone - vasopressin.
Murgatroyd added: "This leaves a permanent mark at the vasopressin gene. It is then programmed to produce high levels [of the hormone] later on in life."
It was concluded that vasopressin was behind the behavioural and memory problems, citing that similarly in humans, childhood trauma can lead to problems such as depression.
Professor Hans Reul, a neuroscientist from the University of Bristol, UK, said: "There is strong evidence that adversities such as abuse and neglect during infancy contribute to the development of psychiatric diseases such as depression.
"This underscores the importance of the study of epigenetic mechanisms in stress-related disorders."
The study was published in journal Nature Neuroscience.