The Impact of Early Childhood Trauma on Brain Development and Attachment

Written by Nadia Hale

Early childhood is a formative time in life where the foundations of our cognitive, social, and behavioural development are established through a complex interplay of biological, psychological, and environmental factors. When trauma occurs in early childhood, it can have profound psychological impacts that alter neurobiological processes leading to maladaptive changes in the brain (Cassiers et al, 2018). 

The relationship between an infant and their mother (or primary caregiver) has been studied through the framework of attachment theory that was first pioneered by John Bowlby in the 1970s. More recent studies in this field have elucidated how the complex interactions between this dyad shape our social, emotional, and cognitive development (Lahousen et al., 2019). 

Early childhood, defined as the ages between 0 to 6 years old, is a critical period of brain development. Fundamental frameworks for cognitive abilities and behaviour are established through complex interactions of genetic, biological, environmental, and psychological factors (Gilmore et al., 2018). Neuroplasticity refers to the ability of the brain to undergo morphological and neurochemical changes in response to stimuli and this occurs through dynamic processes such as synaptic remodelling (Weyandt et al., 2020). In childhood neuroplasticity underlies the ability for rapid learning, skill acquisition and adaptation to new experiences. Trauma is a psychologically distressing experience that induces physiological responses. When trauma occurs in early childhood the brain through neuroplasticity adapts to cope, but later these adaptations become maladaptive in “normal” circumstances. Trauma is defined as any act or series of acts that results in harm, potential for harm, or threat of harm. 

Imagine a foster child that is removed from her mother in infancy. Following this separation is moved from  foster home to foster home. The absence of a consistent and secure attachment figure and constant instability  leads to ongoing stress in the child’s life. It is an unfortunate reality that foster homes a child is moved into to protect them are often places of continued abuse and neglect; It is understood that due to systemic failures some children are exposed to abuse and neglect in foster care (Ainsworth & Hansen, 2014; Crime and Misconduct Commission, 2004). In this example what does research tell us about the possible impacts on the development of that child’s brain. 

There is a large body of research that shows an association between trauma and the deleterious structural and functional effects on the brain (Bryson et al., 2021; Calem et al., 2019; Paquola et al., 2019). In 2016, Paquola et al., conducted a meta-analysis’ and found that a history of childhood trauma was associated with decreased grey matter volumes in the prefrontal cortex, hippocampus, and amygdala, in adult brains. Functional imaging studies found abnormal activation in response to emotional and working memory in the corresponding regions (Hart & Rubia, 2012). These three areas of the brain are not yet matured in early childhood and are undergoing development. The hippocampus undergoes rapid development for the first 5 years of life and, the amygdala and the prefrontal cortex have a protracted period of development that continues into the second decade of life (Lupien et al, 2009). Somatic effects of trauma such as disturbances in the stress axis is identified as one mechanism that mediates these changes in the brain. While all brain areas are sensitive to stress, regions undergoing development have a greater susceptibility (Lupien et al, 2009). 

The adaptive physiological response to stress is glucocorticoid release via the hypothalamic-pituitary-adrenal (HPA) axis and in acutely stressful events this is protective. However prolonged stress causes dysregulation of the HPA axis and the excessive glucocorticoid release is linked to deleterious changes including decreased hippocampal and prefrontal lobe volumes (Pagliaccio et al., 2014). These effects are attributed to glucocorticoid accumulation reaching neurotoxic levels and causing neuronal atrophy and inhibition of neurogenesis (Lupien et al., 2009). In contrast, amygdala hypertrophy is associated with excessive cortisol release; these differential effects may be mediated by different cortisol receptor binding sites in these regions (Pagliaccio et al., 2014). In the amygdala, glucocorticoids stimulate dendritic hypertrophy acting to enhance emotional memory for stressful events (Lupien et al., 2009). 

The cognitive-behavioural component of trauma induced changes are appreciated by considering the differential effects that the subtype of abuse (e.g., neglect, physical and/or emotional) has on the brain. The amygdala has crucial roles in regulating emotions, storing somatosensory information associated with salient memories and evaluating non-verbal communication (Gilmore et al., 2018). Sexual or emotional abuse is associated with amygdala hyperactivity in response to facial expressions (Cassiers et al., 2018). This is thought to be a protective adaptation in these subtypes of abuse due to the importance of responding to facial cues. Whereas neglect results in amygdala hypoactivity due to decreased inhibitory input from higher centres such as the hippocampus and prefrontal cortex (Teicher & Samson, 2016). Teicher and Samson (2016) suggest that the less strongly inter-connected emotional regulatory system is due to the lack of emotional input and environment cues that is characteristic of neglect. 

Translation of research acquired knowledge to an individual child level imparts an awareness of the neurological processes that underlies the cognitive, social, and behavioural issues that manifest in trauma-affected children. They are likely to present with social, emotional, and cognitive difficulties and the associated features are trouble picking up new concepts, falling behind academically and being disengaged from peers. Trauma in early childhood changes the trajectory of brain development and delays maturation of key brain regions required for executive function.

Donald A Barr., (2018) is a professor in paediatrics and outlines the three critical components of executive function that are vital for school readiness which are defined as emotional regulation, cognitive flexibility and working memory. Efficient working memory relies on the hippocampus to convey information to the prefrontal cortex, it is then stored as conceptional memory allowing it to be quickly retrieved (Barr, 2018). Similarly, emotional dysregulation occurs with hyperactivity of the amygdala due to a lack of inhibitory control from higher centres disrupts the formation of new memories (Barr, 2018). Hence executive function depends on the co-ordinated responses between the prefrontal cortex, hippocampus, and amygdala. Trauma-induced changes affect cognitive capacity to form and process new memories, switch from one task to another and think about multiple concepts simultaneously. Delays in the ability to perform executive functioning skills causes a child to not be ready for school, they consequently fall behind, and cognitive processing deficits continue to present learning challenges. 

The heightened amygdala response associated with childhood trauma, results in poor emotional regulation leading to behaviours often deemed disruptive in a classroom setting (Barr, 2018). School could conceivably be a negative place for a child who has learning challenges, struggles to regulate their emotions in the classroom and is consequently labelled a troublemaker. Additionally, emotional regulation is crucial for appropriate behaviour and social interactions between peers. It is not unusual for a child who has experienced trauma to respond to social interactions by becoming anxious, excessively emotional and using avoidance (Adubasim & Ugwu, 2019).   

John Bowlby, a British psychiatrist, during World War II, observed the devastating impacts of institutionalization on children and the difficulties they had forming new attachments (Lahousen et al., 2019).  These observations formed the roots of his attachment theory in the 1970s that is still widely used today. Central to this theory is the concept that the attachment formed between an infant and a primary carer is fundamental to behaviours and relationships later in life. Secure attachment is defined as a specific aspect of this relationship where the caregiver provides a secure base for the child to explore the world and a safe haven when comfort is needed (Benoit, 2004). To form a secure attachment caregiving needs to be predominantly nurturing, attentive and consistent (Lahousen et al., 2019). 

 Attachment is an evolutionary process, and all infants will form attachment with their primary carer even when caregiving is inconsistent, neglectful, or even abusive. In these cases an insecure attachment style develops that is categorised as either avoidant or anxious-avoidant and is defined by a fear of intimacy or abandonment, respectively (Miranda et al., 2019).  A fourth category of attachment style was developed by Mary Ainsworth termed the disorganized attachment style and is typified by infants’ behaviours towards their caregiver that is fearful, conflicted, apprehensive, and disorientated (Rholes et al., 2015). This attachment style has no distinct pattern and is often a result of trauma or a chaotic care-giver (Lahousen et al., 2019).

Since then, attachment theory has continued to evolve, and the psychobiological aspects of the child-caregiver dyad has been studied. This dyad involves complex interactions on psychological and neurobiological levels (Lipp et al., 2009). Ongoing social learning processes occur through this relationship that underpin the development of cognitive mentalization of empathy and emotional regulation in the child (Lipp et al., 2009). Therefore, the quality of attachment not only provides the foundation for positive self-efficacy and the ability to form healthy relationships in the future, but it is also critical for an individual’s mental and emotional well-being.

Socialisation predominantly occurs gradually through a series of interactions in the context of the relationship with their loving parent. The parent steers the child away from anti-social behaviours through modelling, reinforcement, extinction and punishment (Prather & Golden, 2009). Often these interactions are as subtle as a disapproving look. A well-cared for child wants to “please” and be in the presence of their caregiver, so disapproval from the parent is an adequate negative consequence to deter the child from repeating the undesired behaviour. 

Prather (2022) describes how foster children without this influence in their life develop anti-social behaviours like stealing, manipulation and lying. Foster parents struggle to effectively stop these behaviours for the following reasons; i) they lack an emotional bond with the child so the usual contingencies used by parents are absent ii) many anti-social behaviours like lying and manipulation are difficult to detect iii) often the rewards of continuing the anti-social behaviour outweighs the negative consequence (Prather & Golden, 2009).  During adolescence, the foster child is drawn to peers from a similar vein and collectively they further cultivate these anti-social and externalising behaviours. Additionally, disorganized attachment style is associated with engaging in self-injuring behaviours and dissociative personality disorders (Rholes, et al., 2015). Given the prevalence of disorganized attachment in children placed in foster care and the associated externalising and self-destructive behaviours, it is not surprising that this cohort has high rates of juvenile offending and low educational attainment (Ainsworth & Hansen, 2014). Without interventions that create opportunities for children to unlearn these behaviours and have new experiences of relationships, these unhealthy patterns become deeply etched and continue to create obstacles throughout adulthood.

Disorganized attachment styles that continue into adulthood are associated with interpersonal relationship difficulties and poor mental health outcomes. It is widely reported in the literature that insecure attachment styles are predictive for maladjustment and psychopathology including depression, anxiety, and dissociative personality disorders (Benoit, 2004; Dubois-Comtois, 2021). Insecure attachment styles represent relatively ordered responses in relationships predominantly driven by either fear of intimacy or abandonment (Paetzold et al., 2015). In contrast, an individual with disorganised attachment feels conflicted about desiring closeness but simultaneously lacking trust in their partner and their responses are chaotic and incoherent and, this often takes on dysfunctional behavioural patterns (Paetzold et al., 2015). Indeed, Rholes et al, (2015) performed a retrospective study in adults with a history of childhood trauma and found that disorganized attachment patterns in their relationships was associated with externalising behaviour such as aggression and violent tendencies and/or anxiety and avoidance (Rholes et al., 2015).

In conclusion, early childhood trauma profoundly alters the trajectory of brain development through neurobiological adaptations that, while initially protective, often become maladaptive over time. These changes disrupt the maturation of key brain regions responsible for executive functioning, emotional regulation, and learning, while insecure and disorganised attachment patterns further compromise social, emotional, and interpersonal development. Together, these biological and relational disruptions help explain the cognitive, behavioural, and psychological difficulties commonly observed throughout the lifespan. Understanding trauma through both a neurodevelopmental and attachment-informed lens enables practitioners to interpret behaviours as adaptive responses to adversity rather than intentional misconduct. This perspective reinforces the importance of early intervention, stable caregiving relationships, and trauma-informed practice in promoting recovery and improving long-term developmental outcomes. 

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