Research on ACEs and their health impacts

Emerging Minds and ANU, Australia, February

Resource Summary

‘Adverse Childhood Experiences’ (ACEs) is a term used to describe very stressful events or circumstances that children may experience during their childhood, and which can have serious impacts on later life development of chronic diseases, mental health issues and problematic social functioning.

There is an increasing body of evidence on the nature and impact of ACEs on health and functioning, the neurophysiological mechanisms underlying these impacts, and factors that can protect against these impacts.

A range of recent international policy initiatives and programs also reflects growing awareness of the importance of ACEs at population level.

Download a printable full summary of evidence regarding the nature and impacts of ACEs here.

What are 'ACEs'?

Following the seminal 1998 U.S. study involving 17,337 participants in which the term ‘ACEs’ was introduced, the most widely recognised and researched ACEs relate to childhood abuse, neglect and household adversities. These include:

  • childhood physical, sexual and emotional abuse
  • physical neglect and emotional neglect
  • exposure to family violence
  • parental substance abuse
  • parental mental illness
  • parental separation or divorce; and
  • parental incarceration.

While children from lower socio-economic positions may be at greater risk, individuals across all demographics can be exposed to ACEs. An estimated 72% of Australian children have been exposed to at least one ACE, with a higher rate in some vulnerable Australian populations.

The impact of ACEs on health and functioning

Exposure to ACEs can result in developmental delays, lower educational attainment and social and emotional maladjustment. The greater the number of ACEs a child is exposed to (regardless of the particular combination of ACEs), the greater their risk of developing chronic and cardiovascular conditions in adulthood, such as stroke, respiratory disease, diabetes, and cancer. There is also greater probability of health risk behaviours and problematic social functioning – e.g. injecting drug use, teenage pregnancy, violent behaviour, incarceration, depression and attempted suicide.

The poor outcomes of one generation’s exposure to ACEs can form the familial setting that produces the next generation of ACEs affected children. Children who experience ACEs are more likely to have parents who have experienced ACEs. Parents who report four or more ACEs in their own childhood are more likely to have children who are diagnosed with mental health or behavioural problems.

Toxic stress and brain changes: How ACEs influence health and functioning

Exposure to ACEs disrupts brain and neurobiological development in the critical early years of life by triggering a chronic stress response (‘toxic’ stress) which maintains persistently high systemic levels of cortisol. These chronically abnormal cortisol levels affect the development and functioning of brain centres responsible for self-regulation, reward-seeking, executive function and perceptions of threat.

These abnormal cortisol levels are also thought to produce epigenetic changes, triggering a chronic organic inflammatory response that in turn contributes to the onset of ACEs-related diseases.

Resilience and protective factors

Certain protective factors can build a child’s resilience and reduce the impacts of ACEs.

One of the most protective and influential factors in a child’s life is having a safe, caring and supportive relationship with someone they trust. Nurturing relationships form the basis of healthy brain development, effective early learning, and a child’s capacity to positively respond and adapt to life challenges. Having just one positive caring relationship in a child’s life can substantially improve their recovery and healing from adverse events, regardless of the type of adversity.

Appropriate prevention and early intervention measures regarding ACEs, including general practitioners’ advice to parents and referral options, should focus on building and strengthening safe and positive relationships for the child.

International ACEs awareness – emerging initiatives and programs

There is increasing international awareness of the individual and population impacts of ACEs and of the importance of early identification and intervention. For example, Washington State in the USA has enacted legislation to prevent and mitigate ACEs; Wisconsin has conducted a state-population study and declared itself a ‘trauma-informed state’; the National Health Service in Scotland has undertaken to progress action on ACEs; and Public Health Wales (UK) recently sponsored a national population study on ACEs, to develop early intervention programs. Since 2009, 42 U.S. states have collected information on the prevalence of ACEs in their populations.

Up Next The impact of ACEs on health and functioning