Trauma - neurobiology and impacts in mental health conditions

What is trauma?

Trauma can be defined as a deeply distressing or disturbing experience that causes psychological injury or pain.

Some events are more likely to be experienced as traumatic than others; for example, intentional interpersonal violence (e.g. torture, assault) and prolonged/repeated events (childhood sexual abuse, living in a concentration camp) are more likely to result in a traumatic response than a natural disaster (ACPMH, 2007). However, it is important to understand that every person’s response to a potentially traumatic event is different. Some research has found that the combined effect of different types of abuse, including those thought to be less damaging than sexual abuse such as witnessing domestic violence and exposure to verbal aggression, can equal or exceed the impact of sexual abuse alone (Teicher et al, 2006).

Trauma in childhood: the neurobiological impact

Children all over the world are exposed to traumatic events such as natural disasters, abuse, domestic violence, community violence and war. In Australia, common adverse childhood experiences include abuse (emotional, physical, sexual) and neglect (emotional, physical), exposure to domestic violence or relational stress (e.g. separation, depression), alcohol or other substance abuse, mental illness or criminal behaviour in the household. Peer-to-peer violence including bullying and sibling abuse is also significant. If these adverse experiences are extreme and repetitive, and occur during critical periods of brain development, alteration or impairment to the major neuroregulatory systems can occur, creating lifelong neurobehavioural effects (Anda et al, 2006). In simple terms, childhood trauma can alter brain development and as a result, affect human function, behaviours and health outcomes across a lifetime.

While our brains continue to develop throughout our lives, most critical structural and functional organisation of the brain takes place in utero and during early childhood. By the age of 3 our brains are 90% as large as they will be in adulthood (at the same age, the body is only 18% of adult size (Perry, 2000)). Through this period, important molecular processes establish the neuronal organisation and function of the brain and these processes occur in a sequential way i.e. the brain develops from the least complex structure (the brainstem) to the most complex areas (limbic, cortical). The simpler structures controlling basic regulatory functions of the body (e.g. respiration, cardiac function) are predominantly developed in utero and the more complex structures, which impact on future emotional, cognitive, behavioural, social and physiological function, develop during early childhood. The functional and organisational capacities of the adult brain reflect the quality, quantity and pattern of the somatosensory experiences of early childhood. An experience in adulthood may alter the function of the organised brain, whereas an experience in childhood determines the organisation of the brain - the brain adapts to the environment the child is being raised in (Perry and Pollard, 1998).

Just as positive experiences and supportive, enriching environments impact on brain development, so too does adverse experiences and impoverished environments. How the brain is influenced or altered in response to adverse experiences depends on the nature, frequency and developmental timing of the adverse event(s), because brain development is more sensitive at some times than at others (Perry, 2002).

Common reactions experienced during trauma
Emotional responses May manifest as...

Shock, panic, high anxiety, emotionally-numb, feeling stunned, feeling in a fog, denial, dissociation – dazed, apathetic, feelings of unreality, fear, hopelessness, emptiness, horror, terror, anger, hostility, irritability, grief, guilt

(Lerner, 2012)
Cognitive responses May manifest as...

Impaired concentration, confusion, disorientation, difficulty with decision making, poor attention span, vulnerability, forgetfulness, hypervigilance, pervasive thoughts of the event, fear of losing control

(Lerner, 2012)
Behavioural responses May manifest as...

Withdrawal, regressive behaviours, non-communication, changes in speech patterns, impulsivity, erratic movements, aimless walking, pacing, fidgeting, exaggerated startle response, antisocial behaviours

(Lerner, 2012)
Physiological responses May manifest as...

Tachycardia, hypertension, dyspnoea*, hyperventilation, shock symptoms, chest pains*, palpitations*, fatigue, fainting, flushed face, pale appearance, cold clammy skin, increased sweating, thirst, gastrointestinal upset, grinding teeth
NOTE: Not to be confused with symptoms of myocardial infarction (heart attack)

(Lerner, 2012)

The impact of child maltreatment

Child maltreatment in Australia

Between 5-10% of Australian children experience physical abuse, around 11% experience emotional maltreatment and between 12% and 23% witness family violence. Between 7-12% of girls experience penetrative sexual abuse (4-8% for boys), and 23-36% experience non-penetrative sexual abuse (12-16% for boys). There is insufficient research to accurately estimate the prevalence of child neglect in Australia (Price-Robertson et al, 2010). If 'our first intimate or loving relationship with our primary caregiver informs our expectations and patterns of behaviours' into adulthood (Coates, 2010, p392), is it any wonder then, that for some people, the effects of early childhood abuse can be pervasive, widespread and devastating in both the short- and long-term?

The younger a child is when they experience or endure trauma and/or neglect, the more pervasive their problems will likely be. For example, neglect of an infant or young child causes distress for the child because their needs are not being met; lack of physical and emotional stimulation can cause pervasive developmental delay (e.g. delays in language acquisition, fine and gross motor delays, attention problems and hyperactivity, impulsivity, dysphoria, disorganised attachment) and will result in difficulties with cognitive, behavioural, social and emotional functioning. As they grow up, people neglected as infants or children will have developed less capacity to manage later or concurrent stressors. The fact that neglect is often accompanied by exposure to other traumatic events compounds the problems (Perry, 2002).

General effects

People often presume that 'infants and children are extremely resilient, when in fact early childhood is the period of greatest vulnerability to the effects of trauma' (Coates, 2010, p392).

A number of studies have linked adverse early childhood experiences to a variety of negative health outcomes and behaviours which are physical, behavioural and psychological. Physical outcomes include obesity, chronic disease, chronic pain, cardiovascular disease (Happel et al, 2009). Negative behavioural changes include engaging in risk taking behaviour, entering into dysfunctional relationships, aggression and hostility (Wilson, 2010).

Psychological consequences of childhood trauma include interpersonal and relational difficulties, shame, embarrassment, guilt, avoiding care (or increased use of care), low self esteem and cognitive and perceptual disturbances (Havig, 2008). As children, those who live in chaotic environments and experience trauma can find it difficult to form healthy relationships, their social skills learning may be impaired, they may be withdrawn, anxious, mistrusting, or they may use aggression or over-reaction as a coping behaviour (NETI, 2005). Trauma survivors are also more likely to experience a range of problems including emotional instability, difficulty sustaining intimate relationships, vulnerability to further abuse and victimisation, worries about their body and their sexuality, suicidal ideation and suicide attempts, poor social functioning and poor quality of life (Schafer et al, 2011). Women exposed to traumatic events have worse mental health outcomes than men, for a range of biological, social and trauma exposure differences (Schafer et al, 2011).

For young people childhood abuse and neglect is associated with truancy, running away from home and homelessness. It increases the likelihood of being arrested (by 53% as a juvenile and 38% as a young adult) and of being arrested for a violent crime. In juvenile detention facilities, boys are more likely to have witnessed interpersonal violence and girls are more likely to have experienced it (around 90%). Witnessing violence and then re-enacting it is a major cause of societal violence – violent young men are 3-6 times more likely to have witnessed extreme interpersonal or community violence, than those who have not (Hodas, 2004).

Exposure to childhood trauma seems to exacerbate the likelihood of later trauma, particularly for women. Child sexual abuse increases the likelihood of sexual re-victimisation as an adult, increases the likelihood of being raped and increases the likelihood of becoming a victim of domestic violence. About one third of people who are abused as children go on to neglect or abuse their own children – establishing an intergenerational cycle of trauma (Hodas, 2004).

Activation of the stress-response

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The impact of child maltreatment continued

Childhood trauma and mental health

Not all childhood trauma is related to abuse or neglect. Losing a parent, particularly a mother, through permanent separation or death in the primary school years increases the risk of the development of major depression during adolescence and adulthood (Wilson, 2010). However, it is child maltreatment that has the most significant impact on children and the adults they become.

Clear relationships exist between child abuse and a range of mental disorders - clinical depression, anxiety disorders, Post Traumatic Stress Disorder, psychotic disorders, bipolar disorder, eating disorders, substance misuse disorders, reactive attachment disorders, sexual dysfunction disorders, personality disorders and dissociative disorders (Read et al, 2007). The higher the number of adverse childhood experiences, the greater the likelihood of later smoking and substance abuse, suicide attempts, risk taking sexual behaviour, hallucinations, panic, impaired memory and poor anger control (Anda et al, 2010).

Child sexual abuse often co-occurs with other adverse experiences such as marital conflict, parental substance abuse, physical abuse, separation from parents and/or family psychopathology. It is associated with increased rates of depression, alcohol problems, phobias, generalised anxiety, panic attack, drug problems, antisocial behaviours, suicidal ideation and suicide attempts, when compared with the population in general. The effects of trauma are cumulative, so the more severe and prolonged the abuse, the greater the risk of developing a mental disorder (Molnar et al, 2001; Fergusson et al, 2008, p608).

Psychotic illness

About half of all people diagnosed with a schizophrenia-spectrum disorder have experienced one form of childhood abuse (but most - 60-70% - had been subjected to several types). A large UK study found that people who had experienced childhood sexual abuse were 15 times more likely to develop a psychotic illness than people in the general community. Research reveals child sexual abuse in about half of all women and 30-50% of all males, physical abuse in half of all women and men, emotional abuse in 30-60% of women and neglect in 40-60% of men (Schafer et al, 2011; Read et al, 2007).

Adults who have been exposed to trauma and abuse during childhood are almost three times as likely to develop an affective disorder as adults who have not been abused (Hodas, 2004).

Post Traumatic Stress Disorder (PTSD)

Post Traumatic Stress Disorder (PTSD) – where triggers such as physical or mental reminders of the traumatic event e.g. smells, sounds, sights, cause the person to re-live or re-experience the traumatic event(s) - is one of the potential consequences of childhood abuse (Havig, 2008). It is estimated that 17-46% of people diagnosed with schizophrenia also experience PTSD (compared with 3-5% of people in the general population). People with co-occurring psychosis and PTSD are likely to have a history of child sexual abuse as well as poor social support, low socio-economic status, greater exposure to trauma and re-victimisation, lower extraversion and higher levels of neuroticism. They are also more likely to develop substance abuse problems, experience concurrent depression, anxiety and dissociative symptoms.

Photograph of young girl hanging upside down from play equipment at a park.

Borderline Personality Disorder (BPD)

While childhood trauma has not been demonstrated to be ‘causative’ in the development of borderline personality disorder, it is likely to play a role (Ball, 2009). There are strong links between childhood trauma and BPD, particularly when compared with other types of personality disorder. A high proportion of females with BPD have experienced at least one type of childhood trauma and between 40-70% have experienced childhood sexual abuse. The more severe the childhood trauma, the greater the severity of BPD symptoms.

Impact on clinical course

Child trauma also impacts on the clinical course of the mental disorder e.g. in depression, a trauma history increases likelihood of early onset, higher levels of co-morbidity, increased duration of illness, more frequent relapse and/or reduction of the likelihood of remission (Heim et al, 2010). In addition, people with mental disorders and a history of childhood trauma receive more medication, spend more time in seclusion, have higher global symptom severity, are more likely to try and kill themselves and engage more frequently in deliberate self harm than people with a mental disorder but no trauma history (Read et al, 2007).

Interpersonal violence

The World Health Organisation (2004) identifies that interpersonal violence can be sub-divided into two different categories of violence:

  • Family and intimate partner violence - including child abuse, neglect and elder abuse
  • Community violence - including youth violence, rape or sexual assault by an acquaintance or stranger, random acts of violence, violence in institutional settings.

Intimate partner violence

Intimate partner violence is one of the most common forms of violence against women and refers to 'any behaviour within an intimate relationship that causes physical, psychological or sexual harm to those in the relationship' (Krug et al, 2002, p89). Women from CALD communities, Indigenous women and women with a disability are all at greater risk of experiencing intimate partner violence (Vic Health, 2006, p9).

Most women who experience intimate partner violence, experience a number of different types of abuse and most do not disclose their experience due to fear, isolation, shame and lack of support (Mulroney, 2003), despite accounting for over 1/3 of presentations to hospital emergency departments (Vic Health, 2006). Abuse can either be severe and escalating, where the woman is terrorised and threatened and experiencing multiple types of abuse (known as ‘battering’), or more moderate, where occasional eruptions occur (Krug et al 2002, p93).

History of family violence is a powerful risk factor for intimate partner violence by men and having been abused as a child is one of the risk factors associated with experiencing intimate partner violence by women. Pregnancy can also be a trigger point for intimate partner violence (Taft, 2002). Alcohol misuse is a common feature of domestic violence incidents – both in men and women. Drinking increases the severity of aggression, anger and violence. Alcohol is a feature in around 50% of all partner violence situations, 73% of partner physical assaults and 44% of intimate partner homicides. Aboriginal and Torres Strait Islander intimate partner homicides account for 20% of all partner homicides and in 87% of these cases, alcohol has been consumed (Braaf, 2012, p3).

Intimate partner violence is the leading cause of death, disability and disease in women aged 15-44 years (Vic Health, 2006, p8). Survivors are more likely to experience chronic pelvic pain, reproductive health problems, headaches and back pain, and to engage in high rates of smoking, drinking and substance abuse after the violence. Like other forms of trauma, there are strong associations between intimate partner violence and depression, anxiety, alcohol abuse, substance abuse, attempted suicide and somatisation (Roberts et al, 1998).

Photograph of a deserted suburban street

Sexual assault

One in four Australian women experience sexual assault, which includes rape, attempted rape, or sexually motivated violence (e.g. forced kissing, sexual torture), predominantly perpetrated by people that they know (84%). The mental health effects of rape in particular are devastating – survivors of rape are the largest group of people to experience PTSD. And the impact of rape is felt not just by the survivor, but by their family, friends and significant others. Sexual assault is strongly associated with depression, anxiety, substance abuse and attempted suicide. (Campbell and Wasco, 2005).

Women who are particularly vulnerable to sexual assault and at high risk for sexual violence include:

  • women with mental illness
  • sex workers
  • women who are homeless or living in unsafe housing
  • women who are institutionalised
  • women with a disability.

Up to 97% of homeless women with a mental illness have experienced severe physical and sexual abuse. Around 87% of these have experienced abuse both in their childhood and as adults (NETI, 2005). Vulnerable women can find it difficult to end abusive relationships, find it difficult to exercise their rights and difficult to find someone who believes their story (Vic Health, 2006).


Most people (50-80%) who enter mental health services will have experienced complex trauma as well as interpersonal violence (Kezelman and Stavropoulos, 2012; Happel et al, 2009). Indigenous Australians are particularly affected by traumatic events. Loss and unresolved emotional distress (related to racism, loss of land and culture, family separations, deaths in custody, suicide and early death of family members) are endemic (Hart, 2009) and their impact is widespread. For example, 22% of all prison inmates are Indigenous men (Krieg, 2006); Indigenous women are 45 times more likely to be the victim of domestic violence than non-indigenous women (Vic Health, 2009) and Indigenous children experience higher rates of neglect than non-indigenous children (Happel et al, 2009). Similarly, 70-90% of refugees will have experienced pre-migration events which are traumatic - including human rights violations, dispossession, war, organised violence, torture, severe harassment, witnessing the execution, rape or torture of friends or family members, and other threats to life. These trauma experiences can impact on mental health during resettlement (Murray et al, 2008; STARTTS, 2007).

The issue of trauma is painful. The realisation that the majority of mental health service users will have been exposed to or experienced significant trauma in their lives can feel overwhelming for workers. There will also be some practitioners whose own life history includes some of the trauma issues raised in this topic. It is pertinent at this point to remind all health practitioners that self-care is an important part of the work that we do. If any of the information in this topic has been confronting, or disturbing, or too close to home, please ensure that you seek support from a trusted family member, friend or colleague.

It is important to remember that recovery from trauma is possible and there are things that every practitioner can do that will help. The second learning objective of this topic will discuss trauma informed care and trauma informed practices.

Photograph of a young man and young woman walking down an alleyway


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