New insights into the lasting biological and social effects of childhood maltreatment

Childhood maltreatment leaves a lasting impact that goes far beyond physical injuries or fading memories. Scientific evidence has long shown that children who experience abuse and neglect face increased risk of chronic diseases, mental health disorders, and premature death throughout their lives. Beneath these visible signs lies a deeper truth: childhood maltreatment can fundamentally alter a child's biology, triggering molecular changes that can last for decades.

Recent research is unravelling that childhood maltreatment doesn't just harm development-it appears to speed up the aging process itself. Despite growing awareness of the lasting impact of childhood maltreatment, the research fraternity has struggled to understand precisely how these early experiences trigger such deep changes, particularly in very young children. A possible reason is that previous studies have relied heavily on inconsistent biological markers or subjective self-reports and also lacked the tools to simultaneously examine both the biological alterations and social behavioral changes that occur in maltreated children.

To address these knowledge gaps, a research team from Japan's United Graduate School of Child Development-a collaboration between Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University, and the University of Fukui-conducted a comprehensive study examining both biological aging and social behavior in young children. Their findings, published online in the PLOS One journal on May 30, 2025, provide unprecedented evidence and insights into how childhood maltreatment simultaneously accelerates biological aging and impairs social development. The research team included graduate student Keiko Ochiai, Assistant Professor Shota Nishitani, Associate Professor Takashi X. Fujisawa, and Professor Akemi Tomoda, among others.

The researchers studied 96 Japanese children aged between 4 and 5 years, comparing 36 children who had experienced severe maltreatment with 60 typically developing peers. They measured biological aging by looking at DNA methylation patterns using a novel method called the Pediatric-Buccal-Epigenetic clock, which the team has pioneered in their earlier works. These molecular signatures, captured from genetic material from simple cheek swabs, essentially indicate how fast a child's body is aging at the cellular level. Additionally, they used eye-tracking technology to monitor the children's social attention patterns, measuring how long children looked at different elements in carefully selected video footage.

A comprehensive analysis of the data painted a clear yet concerning picture. The team found that children who had experienced maltreatment exhibited significantly accelerated biological aging compared to their typically developing peers. Furthermore, these children spent notably less time looking at eyes when presented with videos of human faces. This reduced attention to eyes-a crucial aspect of social interaction and understanding-suggests there are fundamental differences in how maltreated children process social information. Accelerated biological aging and reduced eye contact were both strongly linked to higher scores on measures of emotional and behavioral difficulties, determined using questionnaire-based tools.

Notably, the researchers found that while accelerated biological aging and reduced eye contact were associated, they appeared to contribute independently to the reported difficulties. This finding highlights that maltreatment may affect children through multiple, distinct biological and social pathways. "Our research sends a powerful message: child maltreatment can leave invisible but measurable marks on a child's biology and social development. By identifying these early warning signs, we can step in earlier and provide targeted support," emphasized Ms. Ochiai.

By providing objective measures of the impact of child maltreatment, these findings also underscore an urgent need for early identification and intervention strategies. "Tools such as eye-tracking assessments and stress-related biological testing could help teachers, doctors, and caregivers expedite the identification of children at risk," remarks Ms. Ochiai. Adding further, she says, "Support programs can then be tailored to improve social skills, reduce emotional stress, and promote healthier development-potentially preventing more serious problems later in life."

Overall, these findings not only deepen our understanding of how child maltreatment shapes development but also offer practical avenues for offering more proactive support. This, in turn, can hopefully assist in providing vulnerable children with the skills and resilience needed for a healthier future.