PSYCHOLOGY WORKS Fact Sheet: Developmental Trauma

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This fact sheet focuses on children and adolescents who have experienced trauma. Trauma is a word that we often hear but may be unsure about its meaning. We can think about trauma as including 3 Es:

Individual trauma results from an event, series of events, or set of circumstances that is experienced by an individual as physically or emotionally harmful or threatening and that has lasting adverse effects on the individual’s functioning and physical, social, emotional, or spiritual well-being (Substance Abuse and Mental Health Services Administration, 2023, p. 2)

There are different kinds of traumatic events. Some might happen one time and have a clear beginning and end, like being in a car accident or in a natural disaster (e.g., hurricane). Other kinds of traumatic events might last a long time, like having a chronic illness or experiencing racism, discrimination, and bullying. For children and youth, traumatic events that last a long time can sometimes start early in life and happen between a child and the adult who is responsible for the child’s care, like a parent or another important caregiver. Examples might be childhood physical, sexual, or emotional abuse; childhood neglect; or being exposed to violence between people. One way of understanding these kinds of longer lasting traumatic events is through a framework called developmental trauma (or complex trauma; The National Child Traumatic Stress Network, n.d.).

In thinking about the types of traumatic events that children and youth might experience, another term that is often used is adverse childhood experiences, or ACEs. When this term was first introduced in the 1990s, it referred to experiences like childhood abuse and neglect, witnessing family violence, living with a parent struggling with substance use or mental health difficulties, having parents go through a separation, and having a parent who is incarcerated (Center on the Developing Child at Harvard University, n.d.; U.S. Centers for Disease Control and Prevention, 2026). Our understanding of ACEs has grown over the years to include other experiences like structural racism, discrimination, poverty, housing instability, and job insecurity. ACEs often are chronic in nature, and some of them fit within the framework of developmental trauma in that these experiences begin early in a child’s life, last a long time, and happen between a child and their parent.

How Might Developmental Trauma Impact Children and Youth?

When a child or youth has experienced traumatic events that can be considered within a developmental trauma framework, the effects can be deep, long-lasting, and show up in many areas of life (Alberta Health Services, n.d.; Center on the Developing Child at Harvard University, n.d.; Cruz et al., 2022; Ford, 2023). This is because these events can cause overwhelming toxic stress that impacts the developing brain and body of a child. Some of the effects can be on:

  • Physical health: sleep problems, changes in appetite, sensitivity to touch
  • Emotions: fear, anger, guilt, sadness, numbness, or hopelessness
  • Behaviour: self-harm, substance use, aggression, or pulling away
  • Thinking and learning: trouble with memory, attention, planning, or problem-solving
  • Relationships: difficulties with trust, staying engaged, handling conflict, or becoming overly dependent

Because developmental trauma can have a range of effects, children and youth might receive various diagnoses that capture these effects. One diagnosis that is related to having experienced a traumatic event is posttraumatic stress disorder (PTSD). This diagnosis may be given to a child or youth who has the following trauma-related symptoms: 1) Intrusion (e.g., re-experiencing the traumatic event through unwanted and distressing memories, flashbacks, or nightmares); 2) Avoidance (e.g., avoiding any reminders of the traumatic event like thoughts, feelings, or certain places); 3) Negative changes in thoughts and feelings (e.g., blaming oneself for the traumatic event, having intense negative beliefs about oneself and the world, feeling disconnected from others); and 4) Changes in arousal and reactivity (e.g., sleep and concentration difficulties, engaging in dangerous behaviour; American Psychiatric Association, 2013). For young children, they might not be able to tell us about their symptoms, but they might show us through their behaviours (e.g., fear, aggression) and play activities that resemble aspects of what they may have experienced.

When providing psychological services with children or youth who have experienced trauma, it is important to ask about the 3 Es—the events that happened, how the young person experienced these events, and their effects on the young person’s well-being. This helps us to see the whole person, to best understand their needs and strengths, and to choose the right supports.

Sometimes, children and youth who have experienced a traumatic event do not show any distress and do not need any mental health treatment. There also are children and youth who show little distress, or their initial distress gets better quickly enough that they can go about their daily activities not too long after the trauma occurred. This is known as resilience. There are many ways to build resilience and address the challenges associated with developmental trauma, but none of them are possible without support and guidance from trusted adults, like parents. These adults can help children and youth to be successful in different areas of their life, to develop positive relationships with others, and to feel a sense of connection at school and in their community (The National Child Traumatic Stress Network, n.d.).

What Support Is Available and How Does It Help?

There are different ways to support children and youth who have experienced trauma. Trauma-specific services (TSS) refer to targeted clinical or therapeutic treatments that specifically address the symptoms and impacts of trauma. These treatments are for children and youth, and they often include important individuals like parents and teachers (DeCandia et al., 2014). Research has identified several treatments that are helpful in improving the mental health of young people who have experienced trauma (Landolt et al., 2024). One widely used treatment, with much research showing that it improves trauma symptoms, is Trauma-Focused Cognitive-Behavioural Therapy (Dorsey et al., 2017; National Institute for Health and Care Excellence, 2018; Thielemann et al., 2022).

Another way to support children and youth who have experienced trauma is through trauma-informed care (TIC). TIC is a universal approach that everyone can have in an organization, like a school or child welfare agency. It is a way of thinking and acting that understands that many individuals may have experienced trauma, violence, or ACEs. In this way, TIC recognizes that everyone needs safe, responsive environments. What this means is that TIC has principles that focus on creating cultures of safety, trust, collaboration, peer support, cultural responsiveness, and empowerment (DeCandia et al., 2014; SAMHSA, 2023). TIC works to identify and change unfair systems or practices, like racism, sexism, or other forms of discrimination, that can cause or worsen trauma for people in an organization. Examples of TIC frameworks are the Attachment, Regulation, and Competency Model (Blaustein & Kinniburgh, 2019) and the Sanctuary Model (https://www.thesanctuaryinstitute.org/).

Whether we are clinicians providing trauma-specific treatment or people that frequently interact with children and youth (e.g., parent, teacher, child welfare worker), TIC approaches help children and youth heal from the harms caused by trauma. Dr. Bruce Perry outlines the 3 Rs (regulate, relate, reason) necessary in any relationship where we want to support a child or youth who has experienced developmental trauma. These steps are (https://beaconhouse.org.uk/wp-content/uploads/2019/09/The-Three-Rs.pdf):

  • Help regulate their emotions and calm trauma-related fight/flight/freeze responses (e.g., take deep breaths together, comfort them with a hug if they agree to physical touch, help them label what they are feeling).
  • Connect and relate through interactions that are sensitive and attuned (e.g., sit and stay with a child or youth when they are having a hard time with feelings or behaviours, let them know you will help them).
  • Support them to reason about a situation by planning, reflecting, problem solving, and organizing (e.g., brainstorm together ways to solve a problem).

When children and youth experience safe, caring relationships and environments that respond to their needs, they can begin to feel safe and trust others; understand how their traumatic experiences have influenced them (and develop self-compassion); and find new ways of connecting with themselves, others, and the world around them. When this happens, it makes an important difference in helping to reduce the effects of trauma. This is how we help children and youth build resilience and achieve their full potential.

When Should I Seek Help for My Child?

If your child has experienced a traumatic event, or if you are concerned about changes that you or others (e.g., teacher, family member) have noticed in your child, you may consider reaching out for professional help. As mentioned earlier, there are many different types of changes that children and youth might experience following a traumatic event. These could include (Alberta Health Services, n.d.; Center on the Developing Child at Harvard University, n.d.; Cruz et al., 2022; Ford, 2023):

  • persistent sleep difficulties (including nightmares) or changes in eating habits
  • intense fear, anger, aggression, sadness, or withdrawal from people or activities that were previously enjoyed
  • difficulties in relationships with peers or adults
  • self-harm behaviour
  • changes in the use of alcohol or drugs
  • not wanting to go to school or be away from a parent
  • changes in school grades
  • persistent difficulties in being able to remember or focus on things
  • play activities where aspects of the trauma are re-enacted

If a child or youth experiences difficulties because of a traumatic event, it is not always possible to predict when these challenges might arise or what form they might take. This is because there are many things that can affect when and how trauma-related distress might be expressed, like the age of the young person, their developmental capabilities (e.g., language use, cognitive ability), and the environment around them (e.g., whether they are safe or still experiencing harm, whether there are supportive adults in their life).

Where Can I Learn More?

Websites

Books from authors who have contributed clinically to our understanding of trauma

  • Burke Harris, N. (2018). The deepest well: Healing the long-term effects of childhood trauma and adversity. Mariner.
  • Herman, J. L. (2001). Trauma and recovery: From domestic abuse to political terror. Pandora.
  • Linklater, R. (2014). Decolonizing trauma work: Indigenous stories and strategies. Fernwood.
  • Perry, B., & Winfrey, O. (2021). What happened to you? Conversations on trauma, resilience, and healing. Flatiron Books.
  • van der Kolk, B. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma. Viking Resources.

References

Alberta Health Services. (n.d.). Trauma training initiative. Information for health professionals. https://www.albertahealthservices.ca/info/Page15526.aspx#tic

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596

Blaustein, M. E., & Kinniburgh, K. M. (2019). Treating traumatic stress in children and adolescents: How to foster resilience through attachment, self-regulation, and competency (2nd ed.). Guilford Press.

Center on the Developing Child at Harvard University. (n.d.). https://developingchild.harvard.edu/

Cruz, D., Lichten, M., Berg, K., & George, P. (2022). Developmental trauma: Conceptual framework, associated risks and comorbidities, and evaluation and treatment. Frontiers in Psychiatry, 13, Article 800687. https://doi.org/10.3389/fpsyt.2022.800687

DeCandia, C. J., Guarino, K., & Clervil, R. (2014). Trauma-informed care and trauma-specific services: A comprehensive approach to trauma intervention. American Institutes for Research. https://www.air.org/sites/default/files/2021-06/Trauma-Informed%20Care%20White%20Paper_October%202014.pdf

Dorsey, S., McLaughlin, K. A., Kerns, S. E. U., Harrison, J. P., Lambert, H. K., Briggs, E. C., Cox, J. R., & Amaya-Jackson, L. (2017). Evidence base update for psychosocial treatments for children and adolescents exposed to traumatic events. Journal of Clinical Child & Adolescent Psychology, 46, 303-330. https://doi.org/10.1080/15374416.2016.1220309

Ford, J. D. (2023). Why we need a developmentally appropriate trauma diagnosis for children: A 10-year update on developmental trauma disorder. Journal of Child & Adolescent Trauma, 16, 403-418. https://doi.org/10.1007/s40653-021-00415-4

Landolt, M. A., Cloitre, M., & Schnyder, U. (Eds.). (2024). Evidence-based treatments for trauma-related disorders in children and adolescents (2nd ed.). Springer.

National Institute for Health and Care Excellence. (2018, December 5). Post-traumatic stress disorder. NICE guideline. https://www.nice.org.uk/guidance/ng116

Substance Abuse and Mental Health Services Administration. (2023). Practical guide for implementing a trauma-informed approach. SAMHSA Publication No. PEP23-06-05-005. National Mental Health and Substance Use Policy Laboratory.

The National Child Traumatic Stress Network. (n.d.). https://www.nctsn.org/

Thielemann, J. F. B., Kasparik, B., König, J., Unterhitzenberger, J., & Rosner, R. (2022). A systematic review and meta-analysis of trauma-focused cognitive behavioral therapy for children and adolescents. Child Abuse & Neglect, 134, Article 105899. https://doi.org/10.1016/j.chiabu.2022.105899

U.S. Centers for Disease Control and Prevention. (2026, March 2). About adverse childhood experiences. https://www.cdc.gov/aces/about/index.html

 

You can consult with a registered psychologist to find out if psychological interventions might be of help to you Provincial, territorial, and some municipal associations of psychology may make available a referral list of practicing psychologists that can be searched for appropriate services. For the names and coordinates of provincial and territorial associations of psychology, go to  https://cpa.ca/public/whatisapsychologist/PTassociations/.

This fact sheet has been prepared for the Canadian Psychological Association by Elisa Romano, Ph.D., C.Psych, University of Ottawa and Delphine Collin-Vézina, Ph.D., McGill University.

Revised: April 2026

Your opinion matters! Please contact us with any questions or comments about any of the PSYCHOLOGY WORKS Fact Sheets:  factsheets@cpa.ca