Dopamine and Drugs — How Neurotransmitters Affect Executive Function
Attention Deficit Hyperactivity Disorder has several theorised causes. To answer the question, "what causes ADHD," we would need to explore several dozen issues that each affect people with the condition in different ways.
Scientists believe that genetics, certain environmental factors, and brain changes may play a role in the development of ADHD. Recent research has also investigated the role of neurotransmitters, especially dopamine.
In this article, we will explore the relationship between neurotransmitters and ADHD, and investigate the various ways in which those of us with ADHD can boost these neurotransmitters to improve our symptoms.
What is a Neurotransmitter?
The different areas of the brain controlling different behaviours and processes communicate with each other via chemical messengers called neurotransmitters. These neurotransmitters allow the different regions of the brain to communicate quickly and efficiently to accomplish key tasks.
In those of us with ADHD, variations in multiple genes cause several of these neurotransmitters to be affected. The ADHD brain either doesn't produce enough of them, or they aren't picked up very efficiently by the brain.
One particular neurotransmitter is thought to play a key role in ADHD — Dopamine.
Dopamine is an important neurotransmitter in the "brain reward cascade" mechanism of the brain. In essence, this mechanism is what we would describe as the good feeling we get after accomplishing something. It allows us to persevere through challenging or unpleasant tasks because we will feel good once it's done.
It used to be thought that the ADHD brain simply lacked dopamine, but recent studies have shown the reality to be a little more complicated. It seems that those of us with ADHD have a higher concentration of dopamine transporters. These transporters remove dopamine from brain cells.
Neurotypical brains have these transporters, too, but when there are areas of the brain which have higher than average levels of transporters, dopamine is removed too quickly. This means that it has less time to exert its effects.
Since the ADHD brain lacks dopamine — or at least the positive effects of it — this means that we get little to no reward from accomplishing tasks, have a hard time persevering through unpleasant (but often necessary) chores, and are easily distracted or diverted from these tasks by the promise of a quick "dopamine fix".
These distractions may be something relatively harmless, such as playing a video game, but they may also take the form of gambling, overeating, drinking alcohol, or taking recreational drugs. These activities are — at their core — our brains looking for a dopamine reward, which comes much less readily to us than to neurotypicals.
ADHD seems to involve a lack of activity in several neurotransmitters in our brains. In particular, four key regions of the brain are affected:
Frontal cortex. This region coordinates several high-level functions, including attention and organisation. A deficiency of neurotransmitters here can cause inattention and disorganisation.
Basal ganglia. This is something of a "control panel" in the brain. Information from all brain regions enters the basal ganglia to then be sorted and relayed to the correct areas of the brain. A deficiency in the basal ganglia can cause information to “short-circuit,” resulting in inattention or impulsivity.
Reticular activating system. This is another "control panel", this time acting as a relay between the many pathways that enter and leave the brain. A deficiency in the RAS can cause inattention, impulsivity, or hyperactivity.
Limbic system. This area of the brain regulates our emotions and our responses to them. A deficiency in this region may cause inattention, irritability, restlessness, or emotional instability.
Each of these four regions interact with each other, and with other regions in the brain and/or body. ADHD may result from a deficiency in one, two, or more of these regions. Furthermore, because they are all interconnected, a deficiency in one area can cause problems in the others.
These deficiencies in the levels and/or uptake of neurotransmitters — and the resulting difficulties in communication between different areas of the brain — make it harder for our brains to accomplish the key tasks that everyone has to deal with as part of regular, daily life. These key tasks are known as our executive functions and include:
Emotion — regulating our emotional responses to situations
Action — self-monitoring and regulating our actions and behaviour
Activation — initiating, organising, prioritising and planning
Focus — focusing, sustaining and shifting our attention
Memory — holding information in our minds as we work with it
Effort — energy levels, sustaining effort, and processing speed
All of these areas are affected by the lack of neurotransmitters in the ADHD brain. It tends to take those of us with ADHD substantially more time and effort to accomplish the same tasks as a neurotypical person throughout an average day.
This additional mental effort can take its toll as we overexert ourselves to meet expectations set by ourselves and others. Even trying our hardest can appear to others as doing the bare minimum or not reaching our full potential.
Spending our lives overcompensating and not addressing the underlying cause can lead to self-esteem issues, anxiety, depression, or cause us to burn out. This is why it's so important to acknowledge, understand, treat, and work with our ADHD brains rather than fighting against them.
What Can We Do?
Thankfully, there are several ways in which we can boost the neurotransmitters in our brains, either by finding healthy ways in which we can produce them naturally, or by taking appropriate medications to improve their production and/or uptake in the brain.
Exercise has emerged in recent years as an effective secondary treatment for ADHD. During exercise, the brain releases neurotransmitters, including dopamine, which is naturally lacking in those of us with ADHD.
Here are some forms of exercise you can try. Some are things you can do alone, others are team sports. Some you can do at the gym or sports club, others you can do at home (and for some, both!).
Swimming Running Cycling Aerobics Dance Tennis Football
Rowing Water Polo Track and Field Boxing Martial Arts Badminton
Hockey Rock Climbing Basketball/Netball Skiing/Snowboarding
Hiking Ultimate Frisbee Lacrosse Gymnastics Swimming
More research is needed to determine the intensity, type and duration of exercise that is most effective at boosting dopamine in humans, but the current research is very promising.
You can read more about exercise and ADHD here.
Many of us with ADHD have issues with sleep, and in turn, issues with sleep can affect ADHD. Lack of sleep can reduce dopamine sensitivity in the brain, resulting in excessive feelings of sleepiness. Getting a good night’s rest may help regulate your body’s natural dopamine rhythms.
Here are some things to try to help you get a good night's sleep:
Try to go to bed and wake up at the same times each day
Take a warm bath or shower
Use aromatherapy oils
Have a warm drink
Eat a healthy snack
Have some quiet time
Have a comfortable sleep environment
Avoid screens for a few hours before bed
Don't start a hyperfocused or energetic activity before bed
Avoid alcohol, caffeine, and nicotine
You can read more about setting up a healthy bedtime routine here.
Mindfulness can be described as the practice of paying attention in the present moment, intentionally and without judgment. Regular mindfulness practice has demonstrated improvements in focus, emotional regulation, concentration, and attention span — all of which are executive functions.
We can create mindfulness moments throughout the day by building it into our everyday routines and activities. Since it is simply paying attention to whatever is happening at the present moment, mindfulness can be practiced almost anywhere and at any time.
As we go about our morning routines, simply drawing our attention to what we're doing is a great way to practice mindfulness.
Throughout the day, pause and ask a question such as, "How am I feeling at the moment?" Listen to the thoughts and feelings in response, considering each in turn without judgment.
This could happen whilst bathing or lying in bed, so needn't take up additional time. Ask questions like, "What went well today, and what didn't?"
You can read more about mindfulness practice here.
Get Enough Sunlight
A condition called Seasonal Affective Disorder (SAD) causes depression-like symptoms in the winter season when they are not exposed to sufficient sunlight. It's thought to relate to the fact that sunlight exposure increases mood-boosting neurotransmitters (including dopamine).
Try to get outside at least once a day, preferably before 10:00 or after 14:00 (between those hours is when the sun may be too intense, risking skin damage).
Medication works by boosting neurotransmitters, so it is a very good way of treating the broadest spectrum of ADHD symptoms quickly and effectively.
More specifically, stimulant medication has been shown to reduce the development of several very serious outcomes such as mood disorders, problems at school, conduct disorders, and substance use disorders.