Excessive stress in early childhood can increase the likelihood of brain disorders and affects an individual's response to stress as an adult, says a new study.The study, on a mouse model, found that childhood stress increases the chance of developing anxiety, depression, or drug addiction later in life by two to four times.In addition, maternal stress during pregnancy may increase the child's risk of developing autism spectrum disorder (ASD) affecting communication and behaviour, psychiatric illnesses, and can also lead to changes in the nutrients a mother passes on to her babies in the womb."Understanding how stress impacts developing biological systems may lead to new, patient-specific approaches to treatment and better outcomes," said Heather Brenhouse, postdoctoral student from the Northeastern University in the US.Further, early life stress was found to change chromatin structure in a brain reward region in mice, making them more vulnerable to stress as adults.Early life stress also accelerates the development of the fear response in young mice. However, the effect can be prevented by blocking stress hormone production, according to the study.Scientists are discovering more about the mechanisms through which childhood or foetal stress disrupts brain development and leads to these disorders, which may help reveal new therapeutic strategies, the team noted.The results were presented at Neuroscience 2018, the annual meeting of The Society for Neuroscience (SfN) in San Diego.The research also suggests novel approaches to combat the effects of stress, such as inhibiting stress hormone production or "resetting" populations of immune cells in the brain.For ASD caused by maternal infection during pregnancy, renewing foetal brain immune cells can alleviate symptoms of the disorder.