Childhood unpredictability linked to higher mental health risks

Children who grow up in unpredictable environments may face elevated risks for depression, anxiety, sleep disorders and other mental health challenges, according to a new study by researchers at the University of California, Irvine, Chapman University and Rady Children's Hospital Orange County, formerly called Children's Hospital of Orange County.

The team learned that both established types of childhood adversity and childhood unpredictability were associated with increased risks for depression, anxiety, behavioral problems, sleep disorders, and physical symptoms such as headaches and abdominal pain. But the unpredictability measure also detected youngsters whose mental health risks were not recognized through typical adversity screening alone.

When researchers combined both measures, they often found stronger links to mental health outcomes than with either individual screening tool. Importantly, unlike many other types of adversity that are difficult to eradicate, parents, families and others can strive to improve the consistency and predictability of children's environments.

Dr. Tallie Z. Baram, study's senior author and co-corresponding authorWhat we discovered in the laboratory mice is that optimal development of the brain depends on consistent patterns, which enable the maturation of brain connections. Like mice, children's brain connections involved in happiness, threat and safety benefit from repeated, predictable experiences. This study shows that those principles matter not only in neuroscience research but also in the lives of children and families from a broad range of wealth and backgrounds."

The work grew out of a collaboration launched in 2021, when researchers from UC Irvine, CHOC and Chapman University received a $2.9 million grant from the California Initiative to Advance Precision Medicine to investigate how to better address the effects of many childhood stresses on neurodevelopment.

For Baram and her colleagues, the project provided a chance to test in real-world settings, with children from diverse backgrounds, a concept that had emerged from years of neuroscience research: that predictable experiences help shape healthy brain development, while unpredictability can leave children more vulnerable to later mental health challenges.

The collaboration brought together neuroscientists, psychologists, pediatricians and data scientists across the three institutions and leveraged California's statewide effort to screen children for adverse childhood experiences (ACEs). California became the first state in the nation to implement a publicly supported ACEs screening program, creating an opportunity to examine how different forms of childhood adversity can influence mental health.

The findings suggest that discoveries originating in neuroscience laboratories can be translated into practical tools that help pediatricians identify children who may benefit from additional support.

Among the study's most notable results is that children who reported high levels of unpredictability despite having no traditional ACEs were substantially more likely to have depression than children who scored low on both measures. The unpredictability screening tool also showed value in recognizing children at risk for sleep disorders.

The study also demonstrated that large-scale screening for childhood unpredictability can be integrated into routine pediatric care. Nearly 30,000 children under 18 were screened at Rady clinics in Orange County during the study period.

For researchers and clinicians, the findings may be especially significant because unpredictability is often something that families, communities and policymakers can address.

Unlike some forms of childhood adversity, unpredictability could be reduced by urging families to establish consistent routines and provide reliable caregiving. Previous research by members of the team found that predictable home environments helped buffer children from the effects of stress and adversity, specifically during the COVID-19 pandemic.

"For parents, this isn't about creating a perfect home," Baram said. "It's about recognizing that consistency matters. Small routines and predictable patterns in daily life can support healthy development."

Funding for the study was provided by the California Initiative to Advance Precision Medicine, the National Institutes of Health, the CHOC Neuroscience Institute, the Donald Bren Foundation, the Danette D. Shepard Foundation and Syntropy Technologies LLC.

Source:

University of California - Irvine

Journal reference:

Glynn, L. M., et al. (2026). Unpredictability is a childhood adversity that contributes to mental health problems. Nature Mental Health. DOI: 10.1038/s44220-026-00681-x. https://www.nature.com/articles/s44220-026-00681-x