Understanding Complex Developmental Trauma
- May 11, 2025
- 3 min read
Updated: Mar 2

A potentially traumatic event is one in which an individual experiences, or is exposed to, a highly stressful and potentially life threatening event. Examples include events such as a serious motor vehicle accident, experiencing or witnessing domestic violence, experiencing abuse or neglect, or the sudden death of a loved one. Complex trauma refers to exposure to repeated and often interpersonal traumatic events. When this occurs during critical early developmental periods, it is known as complex developmental trauma.
Understanding Developmental Trauma
Complex developmental trauma can have a significant impact on a child's developmental trajectory. Exposure can lead to both structural and functional brain differences affecting an individual's capacity to regulate behaviour and emotions. Research indicates changes to the amygdala, hippocampus and prefrontal cortex, all of which play a role in fear processing, leads to difficulties regulating behavioural responses to perceived threats and interference with learning, and higher order cognitive operations such as planning and problem solving. When children are subjected to repeated states of fear and recurring trauma, it changes the way they view other people, the world around them, and their place within it. It teaches young people that the world is not safe and they should remain hypervigilant to threats in order to protect themselves.
People who have experienced complex trauma are more likely to respond to stressful situations encountered throughout life with avoidance, anxiety, anger and frustration. Children exposed to complex trauma face higher rates of poverty, legal problems, violence exposure, substance abuse, attachment issues, financial distress and other health and mental health problems in later life.
Complex trauma interferes with the secure attachment to primary caregivers throughout childhood. Securely attached individuals receive early care that encourages the developmental of internal working models of safety in the world and in relationships with others. Insecurely attached individuals tend to demonstrate avoidant, anxious and disorganised attachment styles leading to relationship conflict and difficulties maintaining stable long term relationships. These attachment styles are often associated with experiences of interpersonal complex trauma.
Common symptoms of Complex Developmental Trauma
Behavioural symptoms that may arise from complex trauma include, hyperactivity, aggression, impulsivity, or conversely, withdrawal and dissociative states.
Children may appear sad, depressed, anxious, and/or angry, while physical signs that may accompany emotional symptoms commonly include complaints of chronic pain or stomach aches.
Cognitive manifestations of trauma include difficulties with attention, motivation, learning new information, memory and information processing difficulties, and challenges with planning and organisation.
Young people with complex trauma symptoms are more likely to be diagnosed with attention deficit hyperactivity disorder (ADHD), conduct disorder, oppositional defiant disorder and bipolar disorder. Some children who show withdrawal or dissociative symptoms or who have developed protective routines or restricted behaviours may be diagnosed with autism spectrum disorders (ASD). Children who have trauma symptoms such as emotional numbing, difficulties interacting with others or challenges with verbal expression may present as similar to children with ASD.
Impact on Daily Life
Complex developmental trauma can have long term effects:
delayed development of personal identity and issues with self-esteem
difficulties in adult relationships especially around trust, vulnerability and intimacy.
challenges with learning and achievement leading to reduced career opportunities.
poor financial stability.
interactions with the justice system are more common.
Repeating patterns of trauma --> intergenerational trauma
The Healing Process
Awareness and acknowledgment of the impact of trauma is a crucial first step.
Accountability is key - accepting that things are not going well, or recognising that dysfunctional patterns of behaviour are causing harm to self or others and that it's time to make a change.
Seeking professional help for healing.
Evidence based therapeutic modalities for treating trauma and complex trauma include; cognitive behavioural therapy (CBT), trauma focused-CBT (TF-CBT), eye movement desensitization and reprocessing (EMDR), dialectical behaviour therapy (DBT) and cognitive processing therapy (CPT).
To begin the healing process, make an appointment with Yellow Psychology. You may be eligible for a Medicare rebate under the Medicare Better Access initiative with a referral and GP Mental Health Treatment Plan. Ask your GP, or contact us for more information.

