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

 This blog discusses key neurotransmitters like dopamine and norepinephrine, highlights the role of brain regions like the prefrontal cortex and basal ganglia, and delves into the interplay of brain networks, such as the default mode network and the cognitive control network. ADHD is not a character flaw but a neurological condition that impacts how the brain processes information and experiences the world.

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 one of the most common mental disorders 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 developmental level. 

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 getting mad and frustrated easily.  

Furthermore, until recently, ADHD has been seen exclusively as a childhood disorder, a disorder that the child may eventually grow out of over time. Over the last 15 -20 years, research (Okie, 2006; Drechsler, 2020) and clinical experience have been able to challenge this assumption by defining and identifying ADHD in adults! Reports estimate 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. Some days, you might find yourself to be a creative powerhouse with ideas popping like fireworks. On other days, you might feel like you are herding a thousand birds on caffeine. At its core, ADHD is about regulation - 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, that requires a little extra understanding, care and support. 

A recent article (Beaton, 2022) looking at the views held by adolescents about their own ADHD, highlighted how they saw themselves as “square pegs” being forced into “round holes” (society/school). The view is that people with ADHD exist in an imbalanced state and that differences are intensified through interactions with others. 

ADHD and the brain

ADHD is not just deficient attention or excessive activity; it is a cluster of behaviours that are, more often than not, seen together. 

Millions of neurons are packed into various regions of our brain, where each region is responsible for a particular function. Some regions interact with the external world to give us our sensory and perceptual experiences and help us understand what to do, while other brain areas interact with our internal world to help regulate our internal systems.

But how does this work? There are several connections or extensive ‘wiring’ that enable these various brain areas to stay linked to each other. Essentially, these ‘wires’ are nothing but the pathways or neural circuits that carry signals and information from one area to another. 

So when one gets neural imaging done, different areas of the brain light up in the brain imaging when these different regions are activated. The brain is such a curious part of us that a lot is going on at any given moment. All this information and signal transmission is further aided by brain chemicals, which we call the neurotransmitters. These ‘chemical messengers’ are the highlight of intricate brain functioning as they stimulate just the required neuron to transmit a travelling signal (neural impulse) from one cell (neuron) to the other cell in the pathway. Imagine each neurotransmitter as a key that unlocks only a specific path, and no other - hence, the neurotransmitters are unique and crucial for the correct ‘wiring’ of different regions of the brain. 

Read more: Dealing With ADHD in Social Situations

What causes ADHD in the brain?

The neurotransmitter, Norepinephrine is released in stressful situations as it helps the body prepare to fight or flight, by increasing the heart rate, shutting down non-emergency work like digestion, and increasing blood sugar levels. Since there are abnormally low levels of norepinephrine production, one with ADHD is often prone to risk-taking behaviours (whether as a child or an adult). 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. The role of reduced dopamine signalling and its impact on attention, impulse control, and executive function has been seen in ADHD.

ADHD and dopamine

Dopamine is the brain's chemical messenger that helps control the brain’s reward and pleasure centre, movement as well as mood. This means that it produces a sense of accomplishment and thereby, feelings of pleasure and motivation. Thus, it is often called the “feel good” hormone. Children and adults with ADHD have low levels of dopamine. Studies show that brain metabolism in children with ADHD is lower in the parts of the brain that control attention, social judgement, and movement (Arnsten, 2010). This is probably why children with ADHD appear restless, adults are unable to finish mentally taxing work and are often seen taking breaks where they move about or switch to something entirely different.

Executive Dysfunction and ADHD

Executive functions are the set of cognitive skills 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 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. Emotional Regulation: Impulsivity is a common feature in most individuals with ADHD and this has been observed to exacerbate 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.
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 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 better 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.

ADHD isn’t a reflection of the person’s character; it’s a condition that influences how one’s brain works. It doesn’t define their worth. 

To one with ADHD: Take pride in your progress, no matter how small it feels. Celebrate your wins. And remember, every moment you persevere, you are showing extraordinary strength.