More Than Just Distracted: How the Brain Functions in ADHD?

How often have we heard of ADHD and googled the same when we realised we are getting distracted, or are unable to finish a task at hand? But is it prudent to label ourselves without truly understanding what ADHD entails? Let’s go through the blog and understand ADHD and how it affects the mind.

What is ADHD?

Attention-deficit hyperactivity disorder (ADHD) is the most common behavioural disorder of childhood. It is a condition where people have difficulty with inattention, hyperactivity, impulsivity, regulating mood, and organisation to a degree that is inconsistent with their developmental level. It is a neurodevelopmental disorder wherein the development of brain functions is different from the usual. 

For example, a child or teen with ADHD may have trouble in school and at home with paying attention, concentrating, losing things, following directions, sitting still, acting without thinking, or moodiness,, as compared to other youngsters of the same age.

As it is a neurodevelopmental disorder, there is a natural improvement in the person’s ability to concentrate. So it was thought that most people with childhood ADHD catch up on their development by adulthood. That is why, until recently, ADHD has been seen exclusively as a childhood disorder, with only a few adults being left with symptoms. However, over the last 15 -20 years, research (Okie, 2006; Drechsler, 2020) and clinical experience have demonstrated that up to 70% of childhood ADHD cases persist into adulthood and that it affects 4.4% of the adult population.

ADHD is not about laziness or lack of intelligence. It’s about how the brain processes attention, impulses, and energy. ADHD is about regulating focus, energy, and actions. It’s exactly why some tasks feel impossible while others (like researching fungi at 1 a.m.) become an all-consuming passion. It is a brain that is wired differently.

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ADHD and the brain

The exact mechanism of how ADHD symptoms are not known. From available research, we can say that the symptoms occur due to interconnections of brain cells that are not conducive to creating longer attention spans. 

To be more explicit, Millions of neurons are packed into our brain. They are interconnected to perform a particular function. The brain receives information from the external environment as well as from inside the body. This information is processed through the networks to understand and interpret the signals and decide on the appropriate responses.

Brain cells are interconnected physically as well as through chemical and electrical connections. The brain is also surrounded by Cerebrospinal fluid, which carries multiple chemicals and hormones. The interconnections and communication are a complex orchestra of physical connectivity, chemical substances and electrical signals that occur at an extremely rapid pace. 

Read more: Dealing With ADHD in Social Situations

In ADHD, almost all neurotransmitters and their balance are impaired. But mainly, a dysfunctional Noradrenaline system is supposed to be the problem.  Norepinephrine is produced in the brain, and the building block of this chemical messenger is found to be dopa, which converts into dopamine, which, in turn, is converted into norepinephrine. 

Thus, norepinephrine is linked arm-in-arm with dopamine.  In the prefrontal cortex and some of its connected regions, there is found to be a dysfunction of dopamine. This creates an inability of the networks there to perform their functions of planning, ordering and implementing different appropriate responses and also avoiding unnecessary and inappropriate responses. Together, this set of abilities is called executive function. 

People with ADHD do not have properly developed executive functions. Dopamine is also a reward hormone. Hence, persons with ADHD are prone to pay closer attention to especially stimulating and rewarding stimuli, including substances of abuse. Sertraline is also important because it is the chemical found in the Ascending Reticular activating system (ARAS), which plays an important role in attentional mechanisms.

More About the Executive Dysfunction and ADHD

Executive functions are the set of brain functions that help with managing oneself and one’s resources to achieve a goal. These skills are used to plan and strategise when managing projects. Children and adults with executive dysfunction often struggle to organise, regulate emotions, set schedules and adhere to routines. 

Here’s how ADHD can interfere with areas like planning, organising, task initiation, time management, emotional regulation, and working memory.

1. Task initiation and completion: Procrastination becomes a crucial problem as starting a task becomes a challenge. Often, they are faced with the issue of leaving the task(s) incomplete and facing undesirable consequences. This happens because the brain is not able to assess and prioritise tasks. The brain’s “reward system” is not engaged until the last moment when urgency or external pressure kicks in. 
2. Time Management: Since prioritising is not at the forefront, there is a lacuna in time management, losing track of conversations, improper estimation of time required to complete work or activities, and an inconsistent internal sense of time. This makes future planning difficult.
3. Working memory: Working memory (WM) is the ability to temporarily store information and process it while performing other mental tasks. Forgetting instructions, losing track of conversations, or struggling to retain multiple steps in a process are some of the challenges faced due to WM deficits, as the person with ADHD finds it hard to manipulate information in real-time.
4. Planning and Organisation: There are challenges in breaking down goals into smaller, actionable steps, organising spaces or thoughts, and keeping track of belongings and deadlines, as the brain’s ability to categorise, sequence, and prioritise may be underdeveloped or function inconsistently.
5. Self-Regulation: Impulsivity is a common feature in most individuals with ADHD. People with ADHD suffer from emotional dysregulation. Overreacting to minor frustrations, difficulty calming down after being upset, and struggling to modulate emotions in social settings are often issues with emotional self-control. Another aspect of regulation is avoiding actions that are unnecessary or harmful. Deficit is what contributes to impulsivity.
6. Self-monitoring: Monitoring one’s progress towards achieving set goals is a problem for individuals with executive dysfunction. They face difficulty in recognising mistakes or adapting to feedback, as sustained attention is often found to be impaired in ADHD.

Brain structures: The four horsemen

• Frontal cortex: The frontal lobes are responsible for a person’s high-functioning abilities as they focus on attention, organisation, and executive functioning. A deficiency of norepinephrine within this brain region might cause inattention, problems with organisation, and/or impaired executive functioning.
• Limbic system: One of the oldest structures of the brain, the limbic system is located deeper in the brain and regulates our emotions. A deficiency in this region might result in restlessness, inattention, or emotional volatility.
• Basal ganglia: The basal ganglia determine and carry out purposeful, goal-directed actions in response to internal and external cues. A deficiency in the basal ganglia can cause information to “short-circuit,” resulting in inattention or impulsivity. Hence, prioritising goal-directed behaviours is thwarted. 
• Reticular activating system: In people with ADHD, the RAS (Raphe Nucleus, mentioned earlier) is dysregulated; this indicates that the sleep-wake cycle is disrupted. The individual’s circadian cycles get skewed, and often it has been seen that there are higher activity levels in the evening, which results in later bedtimes and waking times (Kooij, 2013).

The differences in brain structure and function are not inherently bigger or worse, just different.

Beyond behaviours: The lingering cognitive challenges of ADHD

Neuroimaging studies (Arnsten, 2010) have revealed the structural differences in the ADHD brain. Several studies have pointed to a smaller prefrontal cortex and basal ganglia, and decreased volume of a section of the cerebellum, all of which play important roles in focus and attention. 

This means that ADHD is not a difference in behavioural preference. Instead, ADHD appears to be partially attributed to a difference in how the brain is structured. What may look like behavioural choices: laziness, sloppiness, and forgetfulness are likely due to differences in brain structure and connectivity issues. ADHD is associated with cognitive impairments in inhibitory control and executive function. Compared with average individuals, those with ADHD show deficits in executive functions, especially in tasks involving;

• Making careless mistakes
• Having trouble focusing
• Not listening when spoken to
• Failing to finish tasks
• Having trouble organising
• Avoiding tasks that require mental effort
• Losing things
• Being easily distracted
• Being forgetful

Behavioural manifestations of ADHD, such as restlessness or impulsivity, often decrease in adulthood as one develops coping skills and self-awareness. But cognitive deficits like problems with sustained attention, executive functioning and working memory, persist over time, and an adult with ADHD is not likely to “grow out of it”. 

Why do the Cognitive Deficits persist?

The brain differences associated with the dopamine regulation and prefrontal cortex, wherein planning, prioritising and organising tasks are the major functions, do not get naturally resolved as the child grows older. So even though there might be some behavioural adaptations which ‘mask’ the outward restlessness or impulsivity, the underlying cognitive processes often remain as part of the individual’s lived experiences. 

The final chapter: Brain networks and ADHD

By now, it has been established that in ADHD brains, there is a functional brain network disruption. For most individuals, there is a group of interconnected brain areas that are active when one is either resting or thinking about oneself. This is the Default Mode Network (DMN), which is more active when a person is focusing on internal aspects (memory, abstract thinking, cognition). In other words, when a person is not engaged in a specific task but is experiencing mind-wandering, introspection, or contemplation, the DMN is activated. 

So what happens to someone with ADHD? 

There are essentially two networks: one is the default mode network, and the other is the cognitive control network. The DMN is more active when individuals are at wakeful rest and engaged in internal tasks, such as daydreaming, recovering memories, and assessing others’ perspectives. Conversely, when individuals work on active, willful, goal-directed tasks, the DMN deactivates, and attentional pathways engage. 

In ADHD, the daydreaming brain doesn’t quiet down when the attention circuits turn on. Weak connections between control centres and the DMN cause an inability to modulate DMN activity as per the situational demands for attention. Many studies of children, adolescents, and adults with ADHD, taking and not taking medication, have found that the balance between the cognitive control network and the DMN is either reduced or absent in those with ADHD.

The lack of separation between the cognitive control network and the DMN in the ADHD brain suggests why there are attentional lapses. People with ADHD can instruct their focus control system to pay attention to the task at hand — say, a pile of bills that need to be paid — but the circuits that connect to the DMN fail to send the instructions to quiet down. When the DMN notices a new magazine lying next to the pile of bills, emotional interest centres light up and overwhelm the weak voice of the cognitive centres. Thus, easy distractibility is commonly observed. Prioritising the task that requires attention is found to be a challenge as impulsivity comes to the forefront. 

The Cognitive Execution Network (CEN) refers to a conceptual or functional framework that describes the brain's capability to integrate, coordinate, and execute complex cognitive tasks. Often linked to the dorsolateral prefrontal cortex (DLPFC), the CEN enables higher-order cognitive processes like problem-solving, attention switching, and working memory. Dysfunction within this network can contribute to neuropsychiatric conditions such as ADHD, hence leading to issues with;

• Goal-oriented behaviour and task organisation.
• Error monitoring and adaptive control.
• Flexible thinking and decision-making under changing conditions.
• Suppression of irrelevant stimuli or distractions.

Hopefully, advances in understanding the underlying neurobiology of ADHD will contribute to identifying more specific and targeted pharmacotherapies and will help child neurologists to better manage their patients. Behavioural therapy and pharmacological treatment have both been shown to benefit ADHD patients. But it is also important to see people with ADHD through a lens of compassion.

ADHD is not a flaw or failure; it’s a unique way of experiencing the world. It comes with its challenges, but also with creativity, passion, and resilience that others often overlook.

The brain processes and reacts to life differently, and that difference doesn’t make one less. Yes, the world wasn’t built for the way the mind of an individual with ADHD works. Tasks that seem simple for others—keeping track of schedules, staying organised, or maintaining focus—can feel monumental for them. And that can be exhausting. But it’s not a lack of effort or willpower; it’s a mismatch between the way the world expects them to function and the way their brain is structurally and functionally different.

Conclusion

ADHD is related to a brain that functions differently. So far, certain brain regions and neurohormones have been found to contribute to the problems caused.

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