We already know that difficult childhood experiences can affect mental health in adulthood, but a new study suggests that the impact may be far deeper. According to the findings, stress and distress in the first years of life can alter the communication between the brain and the digestive system and increase the risk of digestive problems even many years later.
The study, published in the journal Gastroenterology, found that childhood stress is associated with changes in the sympathetic nervous system and the communication mechanisms between the brain and the gut. These changes may contribute to the development of symptoms such as abdominal pain, constipation, diarrhea and irritable bowel syndrome.
What happens to the gut when a child experiences stress?
Events such as emotional neglect, family difficulties, dealing with parental mental illness or other traumatic experiences can affect a child's development from the very earliest stages of life.
To understand how stress affects the digestive system, the researchers combined animal experiments with data analysis from two large studies involving tens of thousands of children.
In a study conducted on mice, pups were separated from their mothers for several hours each day during early life. Months later, when they reached young adulthood, they exhibited increased signs of anxiety, sensitivity to abdominal pain and intestinal motility disorders.
The interesting finding was that the effect of stress differed between the sexes: Females tended more to develop diarrhea, while males tended more to suffer from constipation.
More than 40,000 children were examined
The researchers also examined data from more than 40,000 children from Denmark, who were followed from birth until age 15. Approximately half of them were born to mothers who suffered from untreated depression during pregnancy or after childbirth.
The results showed that these children were at a higher risk of developing digestive system problems, including nausea, vomiting, functional constipation, colic and irritable bowel syndrome.
In an additional study, based on data from nearly 12,000 children in the United States, it was found that every type of adverse childhood experience – ranging from neglect to parental mental difficulties – was associated with an increase in the prevalence of digestive system symptoms at ages 9 to 10.
According to the researchers, the findings reinforce the understanding that the connection between the brain and the gut is bidirectional. Mental distress in childhood does not only affect emotions or behavior, but also bodily function and physical health over the years.
The study also revealed that different biological mechanisms are responsible for different symptoms. Some neural pathways were linked to bowel motility problems, while other mechanisms were related to pain. The implication is that in the future, it will be possible to develop more personalized treatments depending on the type of symptoms the patient suffers from.
What does it mean for doctors?
The researchers believe that when evaluating patients suffering from digestive problems, it is important to consider not only the stresses they currently experience, but also their developmental history.
Although the study does not definitively prove that childhood stress causes digestive problems, it joins a long line of research indicating that early life experiences may leave a long-term biological mark on the body.