Early adversity in firstborns linked to 71% higher risk of mental health issues in younger sibling

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Danielle Ellis, B.Sc.Feb 6 2025

Groundbreaking research from UCL reveals that childhood adversity in firstborns increases mental health risks for all siblings, highlighting the need for early intervention and sustained family support

A recent study led by researchers from the University College London, UK, has revealed that firstborns who have gone through adverse childhood experiences have a 71% higher risk of having siblings with mental health problems.

The study, funded by the National Institute for Health and Care Research Policy Research Program, is published in The Lancet Public Health.

Background

Traumatic, violent, or neglectful childhood experiences frequently co-occur within families and can have severe long-term and intergenerational effects on the mental health of family members.

Existing evidence indicates that these adverse childhood experiences affect multiple siblings in a family. However, it largely remains unknown how adverse childhood experiences in firstborns and mothers affect the mental health of other children within the same family. 

In this study, researchers aimed to bridge this gap in knowledge by analyzing linked general practices and hospital health records of 333,048 first-time mothers and their 534,904 children, including both firstborns and siblings, born in England between 2002 and 2018.    

They followed up the entire study cohort from one year before birth to up to 18 years after birth across primary and secondary health care. They specifically focused on six types of adverse childhood experiences in firstborns, including child maltreatment, intimate partner violence, maternal substance misuse, maternal mental health problems, adverse family environments, and high-risk presentations of child maltreatment.

They primarily aimed to examine the association between firstborns exposed to adverse childhood experiences from conception to the age of two years (1000 days) and the risk of mental health problems in multiple children from the same mother (siblings).

Important observations

The study found that about 20% of mothers included in the study have at least one child with a mental health problem, and 1.7% of mothers have two or more children with mental health problems between the ages of five years and 18 years.

Among firstborns included in the study, about 37% had at least one adverse childhood experience, and 10.9% had at least two adverse childhood experiences during the first 1000 days of their life.

The most common childhood adversities were having a mother with mental health issues, followed by adverse family environments, such as parental criminality and homelessness.

Notably, the study found that mothers with firstborns exposed to adverse childhood experiences have a 71% increased risk of having children with mental health problems, as compared to mothers whose firstborn did not experience adversities.

This translated to 12 additional children with mental health problems for every 100 mothers with firstborns exposed to adverse childhood experiences.

Mothers with firstborns exposed to adversities had significantly more children with mental health problems (on average, 30 children per 100 mothers) compared to mothers with firstborns not exposed to adversities (on average, 17 children per 100 days).

The study found a consistently similar risk of mental health problems across siblings in families with firstborns exposed to adverse childhood experiences. There were no differences in mental health problem risk between second-born and firstborn children or third-born and firstborn children.

Regarding mental health outcomes, the study found that in families with firstborns exposed to adversities, about 53% of children have at least one emergency hospital admission for any reason; 10% have at least one mental health-related primary care contact; and 5% have any mental health related hospital contact.

Study significance

This first-of-its-kind study reports that children in families with firstborns exposed to adverse childhood experiences are significantly more likely to develop mental health problems and have higher rates of emergency hospital admissions and mental health-related healthcare use.

Another significant finding of the study is that mothers with firstborns exposed to three or more adversities have the highest risk of having multiple children with mental health problems.

Shabeer Syed, lead author of the article, said, Whilst previous research has focused on the impact of adverse childhood experiences on individual children, our study reveals a cascading health risk that extends beyond the individual, impacting on the health of siblings as well. This likely stems from the continuation of adverse childhood experiences within the family. When a child or parent presents with mental health concerns, violence, or other forms of adversity, it is essential to ask about the wider family context.”

Jessica Deighton, professor at the Anna Freud National Centre for Children and Families and University College London, said, “With escalating rates of children and young people in contact with mental health services, early and effective prevention strategies are the key to improving wellbeing. These findings indicate that, when we encounter children facing significant challenges like domestic abuse or poverty, we must expand our focus to the whole family, including siblings. This would help to ensure all children and young people within families dealing with adversity receive appropriate care as early as possible.”  

To achieve this, we want to see increased funding for prevention schemes and harness community assets – such as GPs and local organizations - which are crucial for helping to identify and meet the needs of vulnerable young people. There should also be, in partnership with diverse groups of children and young people, the development of a comprehensive, cross-government mental health prevention strategy.” 

As mentioned by researchers, the study could not assess adverse childhood experiences related to fathers’ mental health or substance use as healthcare data of fathers are not usually linked to their children.

Moreover, electronic healthcare records often underestimate intimate partner violence and child maltreatment due to non-disclosure or detection and under-recording by clinicians.

Overall, the study highlights the significance of early identification of and sustained support for vulnerable first-time parents and their newborns to reduce long-term mental health problems, healthcare needs, and healthcare costs for the whole family.