Childhood stress rewires the gut-brain axis, and the digestive problems can last into adolescence

When a patient walks into a gastroenterologist's office with chronic abdominal pain, the standard questions focus on diet, stress levels, and recent illness. But a new study suggests clinicians should be asking a different question entirely: what happened in your childhood?

The gut remembers what the brain experienced

Research published in Gastroenterology by a team at NYU's Pain Research Center shows that early life stress - both during pregnancy and in the first years of life - can alter the two-way communication between the brain and the gut, producing digestive problems that persist long after the stressful period has ended.

The study is notable for its breadth: it combines controlled mouse experiments with data from two large human cohorts totaling more than 52,000 children, creating a rare bridge between mechanistic animal work and real-world clinical patterns.

Separated pups, altered guts

In the mouse experiments, neonatal mice were separated from their mothers for multiple hours daily - a standard model for early life stress. Months later, at the equivalent of young adulthood, these mice showed elevated anxiety-like behaviors, increased gut pain, and motility dysfunction.

But the motility problems split along sex lines. Female mice developed diarrhea. Males developed constipation. That divergence is clinically interesting because irritable bowel syndrome in humans also shows sex-based differences in predominant symptoms.

The researchers then probed which biological pathways drove each symptom. Knocking out sympathetic nervous system signaling to the gut resolved motility issues but did not affect pain. Sex hormones appeared to influence pain but not motility. Serotonin-based pathways impacted both.

This dissociation is clinically significant. It suggests there is no one-size-fits-all treatment for stress-related gut disorders - different symptoms may literally require targeting different neural circuits.

40,000 Danish children and untreated maternal depression

The first human study drew on a population-based Danish cohort of more than 40,000 children followed from birth through age 15. Half were born to mothers with untreated depression during or after pregnancy.

Children of mothers with untreated depression had an increased risk of being diagnosed with multiple digestive disorders, including nausea and vomiting, functional constipation, colic, and irritable bowel syndrome. This finding adds nuance to earlier work by the same group showing that maternal antidepressant use during pregnancy is associated with functional constipation in children. The new data suggest that untreated depression may produce even more profound digestive outcomes.

The clinical implication is delicate but important: mothers experiencing depression during pregnancy should be treated, whether through therapy, medication, or both. The digestive consequences for children appear worse when maternal depression goes unaddressed.

12,000 American children and the dose-response pattern

The second human dataset came from nearly 12,000 children in the NIH-funded Adolescent Brain Cognitive Development (ABCD) study. Researchers examined adverse childhood experiences - abuse, neglect, parental mental health problems - and found that gastrointestinal symptoms at ages nine and ten increased with any type of early childhood stress.

Unlike the mouse experiments, the human studies did not find sex-based differences in digestive outcomes. This discrepancy could reflect differences between rodent and human biology, or it could be that the human studies were not powered or designed to detect sex-specific patterns at the same level of granularity.

Different symptoms, different targets

The convergence of animal and human data strengthens the central finding: early life stress reshapes gut-brain communication with consequences that can persist for years. But the mechanistic work in mice goes further by suggesting that the resulting symptoms - pain, constipation, diarrhea - are driven by distinct biological pathways.

Kara Margolis, director of the NYU Pain Research Center and the study's senior author, argues this means treatment strategies need to move beyond broad-spectrum approaches. If sympathetic signaling drives motility dysfunction while serotonin pathways drive pain, a drug targeting one system will not fix the other.

The team is also working on developing antidepressants that do not cross the placenta - a goal that, if achieved, could allow treatment of maternal depression without the downstream effects on fetal gut development that current medications may produce.

The limitations are real: mouse models of maternal separation are imperfect proxies for the complex, varied forms of human childhood adversity. And the human studies are observational, meaning they establish associations rather than causation. But when three independent lines of evidence - controlled animal experiments, a Danish birth cohort, and a U.S. developmental study - all point in the same direction, the signal is difficult to dismiss.