Gaps in knowledge on ACEs

Review shows negative impact of adverse childhood experiences and says understanding must improve.

A better definition of trauma-informed care is needed to test its effectiveness. Picture: stock
A better definition of trauma-informed care is needed to test its effectiveness. Picture: stock

Adverse childhood experiences (ACEs) are a set of 10 negative childhood circumstances involving abuse and neglect that are consistently shown to increase the risk of adult mental health problems and physical diseases. Studies show that the risk of poor outcomes is particularly strong when children have experienced four or more ACEs.

These findings have generated a powerful narrative that has increased public awareness of how early adversity negatively impacts children’s development.

The Early Intervention Foundation (EIF) has completed a comprehensive review of the evidence underpinning this narrative to understand its implications for preventing and reducing ACEs.

It confirmed that ACEs are harmful and strongly associated with serious mental health and behavioural problems. However, it also found that many common assumptions about ACEs are not fully supported by the evidence.

“This means that our knowledge about ACEs is not as strong as many have assumed,” says the EIF’s lead report author Dr Kirsten Asmussen. “It also means that implementing activities that lack clear evidence risks hindering progress and could even make things worse for some families.”

The report provides a follow-up to the 2018 House of Commons science and technology committee inquiry on evidence-based early intervention.

The committee report reflected a strong consensus that ACEs are harmful and associated with a range of negative adult outcomes, but also noted scepticism about the strength of this relationship and the extent to which current practice responses are effective.

Here, Dr Asmussen outlines five key areas where knowledge of ACEs still needs to improve.


By Dr Kirsten Asmussen, head of What Works Child Development at the Early Intervention Foundation

Here are five key things we still do not know about ACEs:

  • We do not know whether ACEs are the root cause of many physical health problems. Although some researchers have argued that ACEs are causally linked to many life-threatening diseases, more recent and robust evidence does not fully support this claim. The implication is that efforts to prevent or reduce ACEs could potentially improve mental health outcomes, but their impact on physical outcomes remains unclear.
  • We do not know the impact of ACEs on adult outcomes in comparison to other negative childhood circumstances. Our review found that while ACEs increase the risk of poor mental health outcomes, other negative childhood circumstances also predict poor outcomes in a way comparable to having four or more ACEs. These negative circumstances include low birth weight, social discrimination and chronic poverty. An over-reliance on the 10 original ACE categories thus risks missing vulnerable children who may also need help.
  • The relationship between ACEs, toxic stress and other biological processes is not fully understood. Recent evidence involving “toxic stress” provides fascinating insight into how negative childhood circumstances could potentially impact the immune and nervous systems. However, most studies to date involve animals or very small samples of humans. More testing is necessary before we understand the implications of this research for child and family interventions.
  • We do not know if ACE screening could cause harm. Routine ACE screening is increasingly used to identify individuals who may be experiencing symptoms of trauma on account of ACEs. However, we still do not know the accuracy of ACE screening for identifying people who need help. We also don’t know whether it could inadvertently re-traumatise some individuals or make them feel stigmatised. Although some studies find that people don’t mind being asked about ACEs, these studies typically do not include individuals who have experienced more than one or two ACEs.
  • The ways in which trauma-informed care might prevent or reduce ACEs remains unclear. Public health agencies are increasingly investing in trauma-informed care as a way of responding to ACEs. However, a wide variety of activities encompass trauma-informed care and the ways in which these activities might improve child and family outcomes is frequently not specified. We therefore need a better definition of what trauma-informed care is and how it helps families so that its benefits can be tested.

What should happen next?

A lack of knowledge about these issues should not stop us from engaging in activities that we do know work. These include 33 child and family interventions listed on the EIF Guidebook with robust evidence of preventing ACEs and reducing ACE-related symptoms. We also know that comprehensive public health strategies that reduce poverty and address social inequalities could also make a positive difference. We therefore recommend that we prioritise these effective interventions and strategies first, before investing more heavily in activities which lack clear evidence.

At the local level, this means increasing families’ access to interventions with robust evidence of working. To do this effectively, local areas must understand the prevalence of ACEs within their communities and where ACEs are most likely to occur. This knowledge should then be used to inform commissioning decisions about evidence-based interventions.

At the national level, ACE-related strategies should include policies that specifically address the social and economic conditions which increase children’s exposure to early adversity.

This means strategies aimed at reducing child poverty and policies that tackle crime and social discrimination. It also means strengthening frontline workforces so that interventions can be delivered to a high standard. Without this additional level of national support, local efforts will have difficulty providing sustainable benefits.

CYP Now Digital membership

  • Policy and research analysis
  • Evidence-based case studies
  • Leadership advice
  • Legal updates
  • Local area spotlights

From £170 /year


CYP Now Magazine

  • Policy and research analysis
  • Evidence-based case studies
  • Leadership advice and interviews
  • Legal updates

From £136 /year