What Are Adverse Childhood Experiences (ACEs)? Trauma-Informed Practice Explained

Adverse childhood experiences (ACEs) are potentially traumatic events and circumstances in the first 18 years of life, such as abuse, neglect, or growing up with domestic abuse, parental substance misuse or mental illness in the home. They are a research concept, not a diagnosis or a screening tool. Large studies link ACEs with poorer health and wellbeing across populations, but a count of someone’s ACEs cannot predict what will happen to an individual child, and many people with several ACEs do well, especially when they have safe, supportive relationships. Trauma-informed practice is about how services behave, not about every worker becoming a therapist.

At a glance: Nexis CPD’s £9 Trauma-Informed Practice and ACEs course pairs well with Safeguarding Children Level 1 and Child Mental Health Awareness. They are CPD accredited and 100% online with a verifiable e-certificate, and any three courses cost £18. This is awareness training and general information, not a therapeutic or clinical qualification, and not clinical or legal advice.

What are adverse childhood experiences (ACEs)?

The US Centers for Disease Control and Prevention (CDC) describes ACEs as “potentially traumatic events that occur in childhood (0-17 years)”. They include things that happen directly to a child, such as abuse or neglect, and things in the child’s surroundings that can undermine their sense of safety and stability, such as living with a parent who misuses alcohol or drugs, or seeing violence at home.

The word “potentially” matters. The same event can affect two children very differently, depending on their age, whether it happened once or kept happening, and, above all, whether a safe adult was around to help. ACEs describe exposure to adversity, not how a person has been affected or who they will become.

ACEs overlap with, but are not the same as, the categories used in safeguarding, which are covered in our guide to the four types of child abuse. Several ACEs are household circumstances rather than abuse, and harms such as bullying, racism, exploitation and poverty are not on the original ACE list.

Where does the idea of ACEs come from?

The term comes from the Adverse Childhood Experiences Study, carried out by Kaiser Permanente, a large health maintenance organisation in Southern California, with support from the CDC. The first major paper, by Vincent Felitti and colleagues, was published in the American Journal of Preventive Medicine in 1998. A questionnaire was sent to 13,494 adults who had recently had a standard medical evaluation with the organisation, and 9,508 (70.5%) replied.

That first paper studied seven categories of childhood experience: psychological, physical and sexual abuse; violence against the respondent’s mother; and living with household members who misused substances, were mentally ill or suicidal, or had been in prison. More than half of respondents reported at least one category and a quarter reported two or more. The researchers found a “graded relationship”: the more categories a person reported, the higher their likelihood of health-harming behaviours and of conditions such as heart disease, lung disease and depression in adulthood.

Later analyses from the same study added emotional neglect, physical neglect and parental separation or divorce, which is where the familiar list of ten comes from. The participants were insured adults in one part of the United States recalling their childhoods decades later, one reason researchers are cautious about applying the findings to individual children in the UK today.

What are the 10 ACEs?

The Early Intervention Foundation’s 2020 evidence review (the organisation is now part of Foundations) describes the ten original categories as five forms of child maltreatment and five serious family difficulties.

• Maltreatment: physical abuse, sexual abuse, psychological (emotional or verbal) abuse, physical neglect and emotional neglect.
• Household difficulties: domestic violence in the home, a household member misusing alcohol or drugs, a household member with mental illness, parental separation or divorce, and a household member in prison.

Different studies word and count these slightly differently. The first Welsh ACE survey, for example, used nine categories and did not ask about neglect. The same review stresses that a focus on these ten “to the exclusion of other factors risks missing people who also need help”, noting that economic disadvantage, discrimination, peer victimisation and child disability are also associated with poorer outcomes.

How common are ACEs in the UK?

ACEs are common. In the first Welsh Adverse Childhood Experiences Study, published by Public Health Wales in 2015, 2,028 adults aged 18 to 69 were surveyed. Population-adjusted figures showed that 47% had experienced at least one ACE before the age of 18 and 14% had experienced four or more. A follow-up Public Health Wales survey, carried out in 2017 and reported in 2018, found broadly the same picture: half of adults reported at least one ACE and more than one in seven reported four or more.

In Scotland, the National Trauma Transformation Programme cites the Scottish Health Survey 2019 as finding that one in seven Scottish adults reported four or more adverse experiences before the age of 18.

These figures need careful handling. The Early Intervention Foundation’s review warns that “current estimates of the prevalence of ACEs are imprecise”, partly because people do not always recall childhood experiences accurately and partly because most surveys use short yes-or-no questions. The practical message is simpler: in any classroom, staff team, ward or caseload, some people will have lived through serious adversity, and usually you will not know who.

Can an ACE score predict what will happen to a child?

No. This is the most important, and most often misunderstood, point about ACEs. An “ACE score” is simply a count of how many categories someone ticked. At population level, people with four or more ACEs have a higher relative risk of many poor outcomes than people with none. But the Early Intervention Foundation’s review explains that “the absolute risk for many outcomes remains comparatively small”, that having four or more ACEs “is not deterministic”, and that an ACE score “is not the best method for predicting the ways in which negative experiences affect the development of an individual child”.

A count also hides what matters most. It treats a single parental divorce the same as years of sexual abuse, it says nothing about when something happened or how long it lasted, and it ignores what helped. The same review raises “serious concerns about the ethics of some ACE screening practices”, including the risk of retraumatising people, of screening without effective support to offer, and of families or individuals coming to define or stigmatise themselves by their score.

For practitioners, that means: do not use ACE checklists to label, sort or predict the future of the people you work with; do not assume that someone with a difficult childhood is damaged, or that someone who seems fine has had an easy life; and treat ACEs research as an argument for prevention and better-designed services, not a tool for judging individuals.

What is trauma-informed practice?

In November 2022 the Office for Health Improvement and Disparities (OHID) published a working definition of trauma-informed practice for the health and care sector. It reflects the definition developed by the US Substance Abuse and Mental Health Services Administration (SAMHSA).

OHID defines trauma as resulting from “an event, series of events, or set of circumstances that is experienced by an individual as harmful or life threatening”. Trauma-informed practice, in its framing, means realising that trauma can affect individuals, groups and communities; recognising its signs and impact; and preventing re-traumatisation. It encourages practitioners to look beyond someone’s presenting behaviour and ask “What does this person need?” rather than “What is wrong with this person?”.

Crucially, OHID is clear that the purpose of trauma-informed practice “is not to treat trauma-related difficulties, which is the role of trauma-specialist services and practitioners”. Instead, it aims to remove the barriers that people affected by trauma can face when using services. A receptionist, teaching assistant or care worker does not need to know anyone’s history to practise in a trauma-informed way.

What are the six principles of trauma-informed practice?

The OHID working definition sets out six principles. The summary list names them as safety, trust, choice, collaboration, empowerment and cultural consideration, and the detailed headings use “trustworthiness” for the second. In everyday terms:

1. Safety: the physical, psychological and emotional safety of service users and staff comes first, including asking people what they need to feel safe and having safeguarding arrangements in place.
2. Trustworthiness: explaining what you are doing and why, doing what you say you will do, and not overpromising.
3. Choice: explaining options clearly and supporting shared decisions.
4. Collaboration: working alongside people and asking what they need.
5. Empowerment: sharing power, validating feelings and concerns, and supporting people to make decisions and act on them.
6. Cultural consideration: moving past stereotypes and biases based on, for example, gender, age, religion, disability, race or ethnicity.

The principles apply to staff too. A team that is kept in the dark and given no say in its work will find it hard to offer safety, trust and choice to anyone else.

Is trauma-informed practice backed by evidence?

Partly, and it is worth being honest about the gaps. OHID’s own definition says the evidence base for trauma-informed practice in different settings “is still being developed” and that the definition will be kept under review. The Early Intervention Foundation’s review found that trauma-informed care “has the potential to improve the quality of practice”, but that what it means “is not well defined”, that practice varies widely, and that there is “limited robust UK evidence” so far that it improves outcomes for children.

That is not a reason to dismiss it: respect, clear explanations, choice and avoiding unnecessary distress are sound practice in their own right. It is a reason to be wary of anyone selling it as a quick fix, and to keep it alongside, not instead of, evidence-based support for families who need more.

How can trauma show up in behaviour?

Children and adults who have lived with ongoing fear or unpredictability may have learned to stay on high alert. Keeping Children Safe in Education 2026 (KCSIE), the statutory safeguarding guidance for schools and colleges in England, notes in paragraph 217 that “a child’s experiences of adversity and trauma can leave them vulnerable to further harm”, as well as facing barriers to attendance, learning, behaviour and mental health.

That might look like a child who reacts strongly to a raised voice or a sudden change of plan, finds it hard to trust adults, seems to switch off, or tests boundaries repeatedly to see whether an adult will stay. In adults it can show up as missed appointments, anger at reception desks or reluctance to accept help. None of these proves someone has experienced trauma, and many have other explanations, including special educational needs, illness, hunger or tiredness.

A trauma-informed response does not mean having no expectations. It means staying calm, keeping boundaries clear and predictable, repairing the relationship after an incident, and being curious about what the behaviour might be communicating. In adult social care the same thinking underpins person-centred approaches to behaviour that challenges, where the starting question is what need the behaviour is meeting. KCSIE paragraph 48 is also a useful reminder that “only appropriately trained professionals should attempt to make a diagnosis of a mental health problem”; staff observe, support and pass on concerns.

What protects children from the effects of adversity?

Relationships, more than anything else. Scotland’s National Trauma Transformation Programme puts it simply: “Adversity is not destiny”, and most people recover well through supportive, positive relationships with family, friends, colleagues, their community and services.

Public Health Wales’s 2018 report on sources of resilience, based on a 2017 survey of 2,497 adults in Wales, found that childhood resilience resources were strongly associated with lower levels of mental illness. Among adults with four or more ACEs, the adjusted proportion currently receiving treatment for a mental illness was 29% for those with low childhood resilience and 14% for those with high childhood resilience. Having a trusted relationship with at least one adult during childhood was associated with a lower risk of current mental illness, and regular childhood sport was also linked with better outcomes. The report is careful to add that resilience “does not provide a panacea” and that preventing ACEs must remain a priority.

Protective factors practitioners can influence include a consistent, trusted adult, a sense of belonging, predictable routines, chances to succeed at something, and support for parents and carers so they can be that steady presence themselves.

What does trauma-informed practice look like in everyday work?

Most trauma-informed practice is small and consistent. It is less about someone’s past and more about how your service feels to use. Whatever your role:

• Explain before you act: tell people what will happen, why, and how long it will take, especially before personal care, examinations or meetings.
• Offer real choices: where to sit, who is present, which order to do things in, or whether to take a break.
• Keep your word: if you say you will phone back on Thursday, do. If you cannot, say so.
• Avoid making people repeat their story: share information appropriately within your policy so they do not have to tell it again and again.
• Notice the environment: noise, crowding and locked doors can feel threatening.
• Stay regulated yourself: a calm voice and steady body language help others to calm down.
• Ask “what happened?” and “what do you need?” before “why did you do that?”.
• Repair after conflict: come back to the relationship once things have settled.
• Do not ask for histories you do not need: curiosity is not a reason to ask someone about past trauma.
• Follow safeguarding procedures every time: trauma-informed practice sits alongside your policy, never instead of it.

In schools and colleges, this might mean a predictable start to the day, a named trusted adult for pupils who need one, warning before changes such as supply cover or fire drills, and behaviour policies that combine clear expectations with a plan for repair. KCSIE paragraph 16 asks staff to think about how best to build “trusted relationships which facilitate communication” with children.

In early years, it means consistent key person relationships, gentle transitions and respectful partnerships with parents who may have had difficult experiences of services themselves.

In health and social care, it means asking before touching, giving people control over the pace of personal care, and recognising that an older person’s distress may be connected to experiences decades earlier.

What should you do if a child tells you they are being harmed?

Trauma-informed practice never replaces safeguarding procedures. If a child discloses abuse, or you are worried about a child, follow your organisation’s child protection policy and speak to your designated safeguarding lead (DSL) or their deputy without delay. KCSIE paragraph 16 reminds all staff that children “may not feel ready or know how to tell someone” and may not recognise what is happening as harmful, and that this should not stop staff from showing professional curiosity and speaking to the DSL.

Being trauma-informed shapes how you respond:

• stay calm and listen, letting the child tell you in their own words;
• reassure them that they have done the right thing by telling you and that they are being taken seriously;
• do not ask leading questions, push for detail or investigate yourself;
• do not promise to keep it a secret, and explain honestly and gently who you will need to tell and why;
• record what was said as soon as possible, in the child’s words, and pass it on as your policy requires.

If a child is in immediate danger, call 999. KCSIE paragraph 50 applies the same route where a mental health concern is also a safeguarding concern. For the wider picture of how safeguarding works, see our guide to what safeguarding children means.

What is vicarious trauma and how can staff look after themselves?

Vicarious trauma is the cumulative emotional effect that hearing about, or responding to, other people’s traumatic experiences can have on staff. It can build up slowly and show up as tiredness, irritability, difficulty switching off or feeling numb or cynical. It is a normal response to difficult work, not a sign of weakness.

The OHID principles explicitly include the safety of staff, and a trauma-informed organisation takes staff wellbeing seriously. That can include:

• regular, protected supervision or reflective practice where staff can talk about the impact of their work;
• debriefs after distressing incidents or disclosures;
• realistic workloads and cover for breaks;
• making it easy to ask for help, including access to employee assistance or occupational health where available; and
• leaders who model the same safety, trust and choice they expect staff to offer others.

Personally, notice your own early warning signs and talk to your manager or supervisor if the work is staying with you. If you are struggling with your own mental health, speak to your GP or contact NHS 111.

How is trauma-informed practice approached in Scotland and Wales?

Scotland has invested heavily in a national approach. According to the National Trauma Transformation Programme, NHS Education for Scotland developed a knowledge and skills framework for psychological trauma in 2017, the National Trauma Training Programme was set up in 2018, and in 2023 it was renamed the National Trauma Transformation Programme to reflect a whole-system approach. Funded by the Scottish Government, it organises the workforce into four cumulative practice levels: Trauma Informed, Trauma Skilled, Trauma Enhanced and Trauma Specialist. The Trauma Informed level is aimed at everyone.

Public Health Wales has run national ACE surveys since its first study in 2015, and the OHID guidance signposts the Trauma-Informed Wales framework as a further resource. Wherever you work, local safeguarding arrangements and your organisation’s own policies set out what you must do.

What trauma-informed practice training is available online?

Nexis CPD’s Trauma-Informed Practice and ACEs course explains what trauma and ACEs are, what the evidence does and does not show, the six principles in action, responding well to disclosures, and organisational culture, staff wellbeing and vicarious trauma. Safeguarding Children Level 1 covers the basics of recognising and reporting concerns, and Child Mental Health Awareness covers children’s emotional wellbeing and when to seek help.

£9 per course. CPD accredited, 100% online, verifiable e-certificate. Pay for 2, get 3 — any 3 courses for £18. These are CPD-accredited awareness courses, not therapeutic, clinical or Ofqual-regulated qualifications. They do not train anyone to diagnose or treat trauma, and they do not replace any statutory or role-specific safeguarding training your employer requires.

Frequently asked questions

What are adverse childhood experiences (ACEs)?

ACEs are potentially traumatic events and circumstances before the age of 18. The ten original categories are physical, sexual and emotional abuse, physical and emotional neglect, and growing up with domestic violence, parental substance misuse, mental illness, separation or divorce, or a household member in prison.

Is an ACE score a diagnosis?

No. An ACE score is a count of how many categories of adversity someone reports. It is a research measure that shows patterns across populations. It is not a diagnosis, and evidence reviews advise against using it to predict what will happen to an individual child.

What are the 6 principles of trauma-informed practice?

The Office for Health Improvement and Disparities’ 2022 working definition lists safety, trust (trustworthiness), choice, collaboration, empowerment and cultural consideration. They apply to how a whole service works, for staff as well as for the people it supports.

Do I need to be a therapist to be trauma-informed?

No. Trauma-informed practice is not therapy. It is about how a service and its staff behave, such as explaining things clearly, offering choice and avoiding re-traumatisation. Treating trauma is the role of specialist services and practitioners.

Does trauma-informed practice replace safeguarding procedures?

No. If a child discloses abuse or you are worried about a child, follow your child protection policy and report to your designated safeguarding lead or their deputy without delay. If a child is in immediate danger, call 999.

Can children who experience ACEs still do well?

Yes. Many people with several ACEs go on to do well. Research from Public Health Wales links childhood resilience resources, including a trusted relationship with at least one adult, with lower levels of current mental illness in adults who experienced ACEs.

This article is general information about adverse childhood experiences and trauma-informed practice, not clinical or legal advice, and it does not replace your organisation’s safeguarding policy. If you are worried about a child, speak to your designated safeguarding lead or local children’s social care, and call 999 if a child is in immediate danger. Nexis CPD courses are CPD-accredited awareness training, not therapeutic, clinical or Ofqual-regulated qualifications.