The far-reaching consequences of child abuse

Maltreatment during childhood is an especially serious risk factor for health problems in the exposed individual, as it brings a host of lifelong consequences. Among the impacts are physical, mental, behavioral, and social ramifications that can continue through pregnancy and parenthood. As a result, adverse experiences during the parents' childhood can affect their own children's development and health.

Higher risk of asthma, ADHD, autism, and depression

In the newly published study, a team of researchers headed by Dr. Claudia Buss, a professor at the Institute of Medical Psychology at Charité, shows that health problems are more common in children of mothers who experienced maltreatment themselves as children. The researchers define maltreatment as physical, emotional, or sexual abuse or neglect by a parent or guardian leading to physical or emotional harm or the threat of harm to a child. They analyzed data on more than 4,300 American mothers and their children from 21 long-term cohorts. Mothers reported on their childhood experiences and provided information on health diagnoses in their biological children up to the age of 18, or this information was collected during visits conducted as part of the study. This valuable trove of data extending across two generations of the same family allowed researchers to identify meaningful connections.

They found that children of mothers who reported adverse experiences were at higher risk of asthma, attention-deficit/hyperactivity disorder (ADHD), and autism. These children also have a higher incidence of symptoms and behaviors associated with depression and anxiety disorders, which are known as "internalizing" disorders. Daughters of mothers in this group are also at higher risk of obesity than their sons. "All of these connections are independent of whether the mother has the same diagnosis," explains Buss, the study's lead author. "That suggests that the risk of that particular health problem is not being transmitted genetically."

First study to cover multiple health outcomes

Researchers have not yet fully decoded the exact mechanisms by which the risk is passed on to the next generation. There are indications that adverse childhood experiences could affect maternal biology during pregnancy, as for example stress hormones. This can affect fetal development in a way that the offspring become more vulnerable for impaired health. There is evidence that biological changes like these are more pronounced in mothers who have developed mental health problems, such as depression, as a consequence of their traumatic experiences. If the mother's mental health is affected by her childhood experiences, this may also impact on how she interacts with her child once it is born, which is likely to be just as important a factor in these multigenerational effects.

"To our knowledge, this is the first study to examine multiple health problems at once in relation to early trauma in mothers in a large, sociodemographically and ethnically diverse sample. That has been done primarily for individual diseases in the past," explains Dr. Nora Moog, also from the Institute of Medical Psychology at Charité and first author of the publication. In keeping with this approach, the researchers showed that children of mothers exposed to early trauma are at greater likelihood of developing multiple physical and mental health problems. The risk is also greater the more serious the mother's childhood experiences were. "At the same time, I should stress that our findings do not mean that all children of mothers with adverse childhood experiences automatically end up with health problems," Buss says, providing context for the group's findings. "The risk is elevated, but it doesn't necessarily lead to a specific health problem."

Early identification and support for those affected

"I assume that appropriate support for mothers who suffer from the consequences of childhood maltreatment can have a positive effect on their health and well-being and that of their children. That means it's very important to identify these mothers and children early on," Buss points out. One way to do this would be to have doctors address parents' own childhood experiences during prenatal or pediatric checkups and provide information on how to contact various support programs or counseling services. This kind of early intervention could help two generations: the parent, who experienced maltreatment and may be suffering from health consequences; and the child, who could be prevented from developing health problems.

Developing new, targeted therapeutic measures will depend on better understanding the exact mechanisms by which the elevated risk of health problems is passed on to the next generation. The research team is currently working on that. The researchers also plan to conduct follow-up studies to investigate which children remain resilient, meaning they do not suffer consequences beyond one generation: What makes them, their mothers, and their social environment different? Beyond that, the father's childhood experiences have received relatively little attention so far, but there are indications that these experiences can also be passed on to the next generation, albeit in some cases by different mechanisms than those involved in mother-child transmission. The researchers plan to explore these research questions in further detail in future projects as well.

About the study

The international team of researchers analyzed the data of 4,337 American mothers from 21 long-term cohorts with an eye to the mothers' childhood experiences. They also examined information on health diagnoses in the mothers' biological children up to the age of 18. The cohort data were provided by a research program named Environmental influences on Child Health Outcomes (ECHO). ECHO encompasses 69 cohorts in the United States. It is supported by the National Institutes of Health (NIH). Dr. Claudia Buss, a professor at the Institute of Medical Psychology at Charité and adjunct professor at the Department of Pediatrics at the University of California Irvine, led the study. She is a principal investigator of a research group within the ECHO consortium and has furthermore received a Starting Grant from the European Research Council (ERC) and funding from the German Research Foundation (DFG) and the German Federal Ministry of Education and Research (BMBF).