5. Trauma as a cause of ADHD

Stress in adolescence and childhood is a common cause of later psychological problems.¹ For example, early childhood stress permanently alters the expression of corticoid receptors and thus the response of the HPA axis to acute and chronic stress.² A basic account of the impact of early childhood stress and its epigenetic manifestation can be found in Eckerle.³

1. Early childhood or chronic stress as an ADHD risk
2. Stressful experiences in childhood and early adolescence cause persistent ADHD in adulthood
3. Traumatic experiences and dopamine

1. Early childhood or chronic stress as an ADHD risk

Many children and adults with ADHD describe sexual abuse and/or trauma.⁴

Several studies confirm a disproportionately increased frequency of early trauma in ADHD sufferers compared to non-affected individuals.⁵⁶⁷⁸⁹¹⁰¹¹¹² The same is true for brain injury trauma and otorhinological trauma. There is debate as to whether causation is involved or whether symptoms of ADHD and trauma overlap. Other sources describe early trauma more generally as a contributor to mental health problems.¹³¹⁴¹⁵¹⁶¹⁷

Early childhood stress (singular traumatic stress) and chronic stress are implicated in the development of ADHD.¹⁸ A Swedish cohort study found traumatic life events 1.8 times more often in ADHD sufferers than in non-affected individuals.¹⁹

20% to 50% of all children who experience early childhood trauma develop clinical ADHD symptoms.¹⁸²⁰²¹
Childhood maltreatment correlates with increased ADHD risk in adults.²²²³²⁴²⁵²⁶²⁷ Children with ADHD are more likely to exhibit abuse. One study found girls with ADHD to be three times as likely to be abused as those not affected. , another study also found children with ADHD to be three times as likely to be abused, as well as a doubled incidence of physical MIssual abuse and a two and a half times increased incidence of emotional abuse.²⁸²⁹³⁰
Childhood maltreatment, particularly emotional maltreatment, also correlates with increased emotional dysregulation and reactivity.²²

One study found a highly significant increase in the frequency of traumatic experiences in ADHD sufferers.³¹ The non-interpersonal events were hardly increased, whereas the interpersonal events were massively increased compared to non-affected persons. See more at ⇒ Trauma as a cause of ADHD.

Traumatic experiences are intense stressful experiences in the broader sense, e.g.:

Frequent separation from caregiver without replacement
Deprivation (emotionally poor relationship of the parents to the child)
Hostile / helpless behavior of the parents towards the child
Long-lasting couple conflicts / marriage problem of parents
Loss of parents³²
War experiences
A study of kindergarten-age children of refugees from war-torn regions showed that they were “more fidgety,” had an enormous urge to move, and found it harder to concentrate. At the same time, they were described as so traumatized that a hot glue gun made them cry. ³³
Shocks (e.g. noise shock)

One affected person reports

An ADHD-HI sufferer:
My mother is definitely an ADHD-HI sufferer. Nevertheless, I always felt safely loved by my parents and my grandmother, who was my main caregiver.
My family reports that I was a pure sunshine as a baby (wish child): cheerful, sleeping well, everything wonderful. Until I suffered a noise shock when I was 2.5 years old (New Year’s Eve firecrackers right outside the bedroom window). My parents claim that I didn’t sleep at all for 3 months. Whether this is true or not - from that time on, according to their reports, I was stressful and anxious. In particular before (at that time still sound barrier breaking and thus enormous bang releasing) jet fighters I had crawled trembling under tables. During nightly thunderstorms I fled panic-stricken into the bed of my parents until the age of 12 or 14. Falling asleep was a drama for decades.

ADHD risk increases with stress level

The risk for children to develop ADHD (odds ratio) increases with the level of psychosocial stress (Rutter Indicator, RI). With an RI of 1, the odds ratio is 7; with an RI of 4, it is 41.7.³⁴
Odds ratios > 1 indicate increased risk. Disorganized attachment behavior is a risk element of ADHD.³⁵ Attachment disorders of children in the first years of life lead to an activation of the DRD4 gene, which is also common in ADHD, if there is a corresponding genetic disposition.³⁶

Massive maternal stress in the early years of childhood causes significant epigenetic changes in the children’s DNA.³⁷

Emotional abuse and physical abuse significantly increase the risk for ADHD and ADHD symptomatology, as do adverse life circumstances and school anxiety.³⁸

A study of 110 boys found a highly significant increased frequency of traumatic experiences in ADHD sufferers.³¹

The Life Incidence of Traumatic Events (LITE-P) test asks:

Child experienced car accident
Child injured or hospitalized in other accident
Nearby person injured
Family member in hospital
Death of a family member
Friend sick or died
Child experienced fire
Child experienced natural disaster
Mutual injury/destruction of things between adults
Separation / divorce parents
Abuse of the child
Child tied / locked up
Abuse of the child
Child threatened
Child robbed

On average, the 65 ADHD-affected boys had experienced almost every type of trauma more frequently than the 45 boys in the comparison group. The interpersonal events (traumas in the relationship context) were significantly higher than the non-interpersonal events. The number of relationship-relevant IPE traumas also correlates with the intensity of hyperactivity and the overall symptomatology. Age-related inattention symptomatology also correlates highly significantly with the number of IPE traumas.

Several other studies have come to comparable conclusions.³⁹⁴⁰
Trauma from emotional neglect or abuse significantly increased the likelihood of ADHD.⁴¹

In contrast, another study reported that victimizing trauma increased the likelihood of ODD, but not ADHD.⁴²

Assuming that one third⁴³ to one half of all children and two thirds of all children in psychiatric samples show trauma, a frequent overlapping of ADHD and early childhood trauma is to be expected.⁴⁴ However, this alone does not explain why studies on trauma as a (co-)cause of ADHD have overwhelmingly found a higher number of early traumas in ADHD sufferers than in nonaffected individuals.⁴⁵

One developmental pathway of ADHD is attributed to genetic causes in conjunction with environmental experiences, and these environmental experiences may be early traumas.⁴⁶

Hypothesis on trauma as a cause of ADHD

Since ADHD correlates with a too wide open stimulus filter, which on the one hand can be a consequence of stress dysregulation, but on the other hand can also be understood as an expression of the genetic disposition for ADHD (high sensitivity), the question arises whether the early childhood stress load manifesting ADHD cannot be understood as a low-threshold traumatization of highly sensitive natures. It is likely that early childhood multiple traumas can trigger ADHD if there is a genetic predisposition. The more sensitive a person is, the lower is the required impact of a threatening stress situation to neurologically implement a traumatizing manifestation of stress regulation dysfunction.
It is well known that different personality types react differently to environmental influences. Introverts react more intensively to environmental influences than extroverts.⁴⁷ The concept of high sensitivity according to Aron is closely linked to introversion.

This raises the question of whether such a low-threshold traumatization of those affected, which in the case of ADHD, to remain in this image, also typically occurs in the first 6 years of life, is at all amenable to therapeutic intervention and analysis.

The

low memory capacity of people for events in the first years of life on the one hand and
on the other hand, the fact that even impacts far below what non-affected people would consider a serious trauma-causing event can trigger a traumatizing reaction in genetically predisposed people,

could obscure the view of such a cause.

Following this line of thought, the principles of EMDR therapy, which is recognized as effective for trauma, may be transferable to ADHD.

In trauma and PTSD, there is partial overactivation of the PFC, which can be effectively reduced by the bilateral sensory contacts in EMDR, which at the same time correlates with the degree of reduction in PTSD symptoms.⁴⁸

ADHD-affected children are also more likely than average to be victims of violence and bullying (as a result of ADHD).⁴⁹

2. Stressful experiences in childhood and early adolescence cause persistent ADHD in adulthood

A study of stress levels in children with ADHD found that severe stress levels in childhood and adolescence were associated with severe ADHD-HI or ADHD-I progression into adulthood, whereas children with mild stress levels in childhood and adolescence often showed remitting ADHD (ADHD-HI as ADHD-I).⁵⁰

3. Traumatic experiences and dopamine

Although it is not yet proven that (early childhood) trauma increases ADHD risk (causally) by altering the dopaminergic system, there is strong evidence that trauma, both early childhood and adolescence, permanently alters the brain’s dopaminergic system.⁵¹⁵²⁵³⁵⁴ One mediator could be that stress alters the HPA axis, which in turn exerts an influence on dopamine synthesis and dopamine receptors.⁵⁵

The main dopaminergic nodes of the stress network in the brain are

Medial prefrontal cortex (mPFC)⁵¹⁵⁶⁵⁷⁵⁸
Nucleus accumbens⁵⁶⁵⁷⁵⁸
Striatum⁵⁷⁵⁹⁵⁸

Rodents show after early stress

Flattened dopamine stress response in the mPFC⁶⁰⁶¹
Increased tonic dopamine levels in subcortical areas⁶²
Increased noradrenaline release on acute stress⁶⁰

Early childhood stress appears to cause an increased dopamine stress response in the striatum later in life⁶³⁶⁴

In humans, the dopaminergic system is primarily controlled by dopamine D2 and D3 receptors in most nodes of the stress network.⁶⁵⁶⁶⁶⁷

Trauma in childhood correlated positively with D2 receptor availability in males and in females.⁶⁸

Early childhood trauma correlates with decreased levels of the dopamine breakdown product homovanillic acid in blood plasma⁶⁹ and cerebrospinal fluid⁷⁰.
One study reports a coorelation between the spatial extent of dopamine activity in the mPFC during acute stress and the severity of the stress experience in early or later childhood.⁷¹

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5. Trauma as a cause of ADHD

1. Early childhood or chronic stress as an ADHD risk¶

2. Stressful experiences in childhood and early adolescence cause persistent ADHD in adulthood¶

3. Traumatic experiences and dopamine¶

1. Early childhood or chronic stress as an ADHD risk

2. Stressful experiences in childhood and early adolescence cause persistent ADHD in adulthood

3. Traumatic experiences and dopamine