Intriguing Brain and Neurochemical Pathway Similarities Between ADHD and CPTSD

In my last post, “Understanding the Overlap: How ADHD and Complex PTSD Manifest Similarly in Daily Life,” I highlighted many overlapping symptoms between Inattentive-ADHD (often experienced by women, but not exclusive to them) and Complex PTSD (a condition resulting from prolonged traumatic experiences, often in childhood, with no escape). The post covered how these symptoms manifest in our daily thoughts and behaviours and how they play a vital role in shaping our sense of identity.

Just to recap:

ADHD (in girls and women)	Symptom/Manifestation	CPTSD (generalised across genders)
Yes	Inattention	Yes
Yes	Verbal impulsiveness/inappropriate talkativeness/faster talking	Yes
Yes	Faster completion of school work	Unknown
Yes	Easily bored (when not offered something of interest)	Yes
Yes	Difficulty in waiting their turn	Unknown
Yes	Moodiness, anger, and stubborness	Yes
Yes	Depressive symptoms	Yes
Yes	Negative effects on self-esteem	Yes
Yes	Difficulty in focusing	Yes
Yes	Forgetfullness	Yes
Yes	Poor coordination	Unknown
Yes	Anxiety	Yes
Yes	Failure to complete tasks	Yes
Yes	Racing thoughts	Yes
Yes	Masking (hiding symptoms and internalising)	Yes
Yes	Difficulty getting on with parents and making friends	Yes
Yes	Cognitive and attention impairment	Yes
Unknown	Dissociation	Yes
Unknown	Few memories of childhood	Yes
Unknown	Hypervigilance	Yes
Unknown	Can read the energy of a room, fully on guard	Yes
Unknown	Avoidant-attachment	Yes
Unknown	Codependency	Yes
Yes	Promiscuity	Yes
Yes	Feelings of being left out, loneliness, lack of belonging	Yes
Yes	Low self-worth / worrying about people think of them	Yes
Yes	Rejection Sensitivity Disorder	Yes
Due to social pressure to fit in	People pleasing	Due to seeking acceptance and love
Unknown	Flashbacks and triggers	Yes
Unknown (I imagine yes due to ‘masking’)	Repressing ones needs and feelings	Yes
Unknown	Perfectionism	Yes
Yes	Shame	Yes
Yes	Poor time management	Yes
Yes	Poor organisation	Yes
Yes	Scattered thoughts	Yes
Yes	Prone to overwhelm	Yes
Yes	Procrastination	Yes
Unknown	At home with conflict, attracted to working to be loved or chosen	Yes
Unknown	Difficulting in relationships: skin uncomfortable with touch, racing heart with fear of betrayal, intense sensations to run or ghost, high reactivity	Yes
Unknown	Lack of trust – overly independent, can’t rely on anyone	Yes
Unknown	Fear of being a burden to others, so become overly considerate or won’t ask for help	Yes
Unknown	Feeling guilty for resting – ashamed of resting, a need to be useful and productive all the time	Yes
Yes	Constantly stressing about the future – never feeling good enough or feeling I’m never going to amount to anything	Yes
Unknown	Prolonged elevated level of performance (over longer lengths of time, such as years, rather than in a prolonged hyper-focused state)	Yes
Yes	Suppression of symptoms / not being aware that I have symptoms	Yes
Yes	Exhaustion and physical discomfort	Yes

ADHD, CPTSD, and the Brain

This post delves into the brains and neurochemical pathways of individuals with ADHD and CPTSD, highlighting similarities in deficits and fluctuations within brain areas, neurotransmitters, and hormones. It explores how these changes lead to issues with cognition and emotional regulation compared to individuals without these conditions.

Attention Deficit Hyperactivity Disorder (ADHD) and Complex Post-Traumatic Stress Disorder (CPTSD), including Post-Traumatic Stress Disorder (PTSD), are distinct neuropsychiatric conditions often examined in isolation. However, emerging research highlights intriguing similarities in the brain structures and neurochemical pathways affected by these disorders. Understanding these overlaps can provide valuable insights into their underlying mechanisms, potentially leading to more effective, targeted treatments.

The ADHD Brain

ADHD affects how the brain works in several key ways, and these differences help explain the behaviours often seen in people with the condition.

Prefrontal Cortex (PFC)

The Dual Pathway model explains that issues with attention and executive functions (like planning and organising) are linked to problems in the prefrontal-striatal circuits. Hyperactivity is related to problems with how the brain responds to rewards and motivation, involving the frontal-limbic system.

The Prefrontal Cortex, particularly in the right hemisphere, is weaker in function and structure in those with ADHD¹. This area is crucial for regulating attention, behaviour, and emotions. Children with ADHD often have a prefrontal cortex that matures more slowly and is slightly smaller², contributing to issues with self-control and focus.

People with ADHD show reduced activation in the striatum^{3 4} which is highly interconnected with prefrontal cortical areas. The striatum is involved in various functions, including reward perception and decision-making. Reduced activity in this area can lead to difficulty staying motivated and focused on tasks, making it harder to complete activities that aren’t immediately rewarding, especially those requiring long-term effort.

Dopamine Levels

Lower levels of dopamine in people with ADHD suggest additional brain pathway issues. Dopamine helps regulate attention and reward. The reduced levels in the prefrontal or cingulostriatal pathways might explain why people with ADHD have significant difficulties with inattention.^{5 6 7}

Frontal Lobes and Other Brain Areas

The cerebellum, hippocampus, and amygdala are smaller in children with ADHD⁸, affecting memory regulation, emotion, and behaviour. These differences become less significant by adulthood.

Cerebellum: Scientists have found that “damage” to the cerebellum can interfere with a person’s balance while standing or walking, and their ability to reach for objects, judge the size of or distance from objects, and affect their sense of timing. It can also make it harder for a person to learn new words or skills (Cleveland Clinic).

People with ADHD also often have working memory deficits. Studies^{9 10} show less activation in the left posterior lobe of the cerebellum during tasks requiring working memory. As mentioned, the cerebellum, especially the posterior inferior vermis, is significantly smaller in youths with ADHD, impacting their ability to remember and process information in the short term¹¹.

Hippocampus: The hippcampus has a major role in learning and memory, spatial navigation¹², emotional behaviour¹³, and regulation of hypothalamic functions¹⁴ such as heart rate, blood pressure and body temperature. Though emotional behaviour is regulated mainly by amygdala, hippocampus and amygdala can influence each other (latter affects more than former)¹⁵. 

Amydala: is a major processing centre for fear and emotional responses. It also links emotions to many other brain abilities, especially memories, learning and senses.

A smaller hippocampus and amygdala leads to heightened emotional activity, resulting in increased emotional outbursts. Deficits in these areas also affect learning, memory, and their other functions.

So, the research shows that smaller size and reduced activation in these brain regions in children with ADHD affect memory regulation, emotion, and behaviour. Personally, I continue to experience problems with memory regulation and emotion into adulthood.

Note: It’s crucial to understand that “smaller” does not equate to “less intelligent” (Psychology Today, 2021).

“It may be that these regions are used less in people with ADHD. Or that they are smaller because they are organized differently, or because the supporting tissue is different” (Surman, 2017).

Default Mode Network (DMN)

The DMN, which activates when daydreaming or not focused, is more active in those with ADHD. This means that people with ADHD are more likely to have their focus pulled away from tasks toward unrelated thoughts, which can lead to “careless” mistakes.¹⁶

Reading Difficulties (RD)

ADHD often coexists with reading difficulties (RD). Both conditions share neural deficiencies during attention tasks, indicating common underlying brain mechanisms¹⁷. This overlap can complicate learning and academic performance.

ADHD and Hormones

ADHD is often associated with hormonal imbalances¹⁸, which can affect neurotransmitter regulation and contribute to the disorder’s symptoms.

ADHD Conclusion

Understanding these brain and neurochemical differences in ADHD is crucial for developing targeted treatments that address specific neural pathways involved in the disorder. This knowledge can help create more effective strategies to manage ADHD symptoms and improve the quality of life for those affected.

The CPTSD Brain

Trauma significantly impacts the brain, leading to both structural and functional changes. These alterations affect various brain regions and biochemical processes, resulting in a wide range of psychological and physiological effects.

Derangement of Cortisol Levels

Elevated cortisol levels are a common response to stress and trauma. Cortisol, a hormone released by the adrenal glands, helps the body manage stress. However, trauma can lead to prolonged elevated cortisol levels¹⁹, causing various adverse effects on the brain. By contrast, exposure to severe abuse during infancy is associated with lower levels of glucocorticoids in both primates and humans²⁰.

Lower cortisol levels can cause fatigue, unintentional weight loss, poor appetite, and low blood pressure (hypotension)²¹.

Dopaminergic Reactivity

There are studies that show low levels of dopamine in PTSD and trauma patients^{22 23 24} which can contribute to symptoms such as a lack of interest, enjoyment or pleasure from life’s experiences and impaired motivation. Other studies show that genetically determined changes in dopaminergic reactivity/a heritable path may contribute to the occurrence of PTSD among trauma survivours^{25 26}. However, research on the links between trauma and dopaminergic pathways is still limited, and these connections need more validation before we can be certain.

Medial Prefrontal Cortex (mPFC) Dysfunction

The medial prefrontal cortex (mPFC) plays a crucial role in regulating emotional responses and decision-making. Trauma can lead to the underactivity of the mPFC^{27 28 29}, impairing its interaction with the hippocampus, which is essential for memory consolidation and emotional regulation.

For instance, the more active left ventral anterior cingulate cortex (ACC) in individuals with severe childhood abuse experiences can lead to heightened emotional responses. This means they might experience intense emotions more frequently, making it harder to manage everyday stressors.

The increased brain activity linked to processing negative information can interfere with other cognitive functions such as attention, decision-making, and problem-solving. This might make it harder for individuals to focus on tasks, make decisions, or solve problems effectively.

Complex PTSD can significantly impact working memory^{30 31 32}. This impairment is due to a combination of emotional dysregulation, heightened stress responses, impulsivity, interpersonal stress, attention deficits, and neurobiological changes. These factors deplete cognitive resources, disrupt focus, and hinder the brain’s ability to hold and manipulate information, leading to notable challenges in tasks that require working memory.

Reduced Oxytocin Production

Oxytocin, often called the “love hormone,” is crucial for social bonding and emotional attachment. Low oxytocin levels have been linked to trauma, borderline personality disorder (which is thought to be closely related to traumatic experiences in childhood), schizophrenia, and autism, resulting in difficulties in forming trusting relationships and increased social anxiety and difficulty with maintaining emotional connections. Researchers are currently researching the postive effects of using synthetic oxytocin as a treatment for these conditions. Though very interesting, the research results are still mixed, so these connections need more validation before we can be certain. ^{33 34 35 36 37}.

Overactive Amygdala

The amygdala is the brain’s primary centre for processing fear and emotional responses. Trauma can result in an overactive amygdala^{38 39}, leading to heightened anxiety, hypervigilance, and an exaggerated stress response.

Shrunken Hippocampus

Individuals who experience depression or post-traumatic stress disorder (PTSD) often show reduced hippocampal volume in their brain scans^{40 41 42}, leading to heightened emotional activity and deficits in learning and memory functions.

Accelerated Erosion of Telomeres

Telomeres are protective caps on the ends of chromosomes necessary for DNA replication, which is essential for all living things, including humans, to continue living. These caps shorten with age. Trauma has been linked to accelerated telomere erosion, which is associated with premature aging and an increased risk of various diseases.^{43 44 45}.

Trauma Conclusion

Trauma profoundly impacts the brain, leading to elevated cortisol levels, mPFC dysfunction, potentially reduced oxytocin production, overactive amygdala, and accelerated telomere erosion. These changes contribute to various psychological and physiological difficulties, emphasising the need for effective trauma-informed care and interventions.

Shared Brain Structures and Neurochemical Pathways in ADHD and CPTSD (PTSD)

Here’s a quick glance at the shared brain structures and neurochemical pathways in ADHD and CPTSD (PTSD).

ADHD (in girls and women)	Brain Structure/Neurochemical differences from control groups	CPTSD (generalised across genders)
Yes	Smaller and underactive pre-frontal cortex affecting reward pathways, self-control and focus, planning and organising, emotional responses, decision-making, and working memory.	Yes
Yes	Overactive amygdala affecting stress hormone activation, fear and emotional responses.	Yes
Yes	Shrunken hippocampus affecting spatial navigation, learning, regulation of hypothalamic functions, and memory consolidation.	Yes
Yes	Low dopamine levels affecting inattention, motivation, enjoyment or pleasure from life’s experiences, and movement control.	Jury’s out
Yes	Low norepinephrine levels46 47 48	Unknown

Treatments

Treatment for CPTSD often involves a combination of psychotherapy methods, including cognitive behavioural therapy (CBT), dialectical behaviour therapy (DBT), and eye movement desensitisation and reprocessing (EMDR), among others. The approach is usually tailored to the individual and may involve building skills to cope with emotional dysregulation, processing traumatic memories, and working to reconstruct a positive self-image and sense of identity.

Treatments for ADHD typically include a combination of medication, such as stimulants or non-stimulants, behavioural therapy, psychoeducation, and lifestyle changes like improved diet, regular exercise, and adequate sleep.

Conclusion

In this post, we have delved into the fascinating overlaps between ADHD and CPTSD (PTSD), focusing on the similarities in brain structures and neurochemical pathways. By examining the deficits and fluctuations within key brain areas, neurotransmitters, and hormones, we can better understand how these conditions affect cognition, emotional regulation, and behaviour compared to individuals without these conditions.

Both ADHD and CPTSD are distinct neuropsychiatric disorders, often considered in isolation. However, the emerging research highlights that there are significant similarities in the brain’s structural and chemical alterations caused by these disorders. This insight is crucial as it opens new avenues for understanding their underlying mechanisms, which can lead to more effective and targeted treatments.

Understanding the shared brain and neurochemical characteristics of ADHD and CPTSD can help develop better treatment strategies and improve the quality of life for us who are affected. By shedding light on these overlaps, we can move towards a deeper understanding of living with these complex conditions.

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