ADHD, Dopamine, and Desire

In most discussions about Attention-deficit/Hyperactivity Disorder (ADHD), when a reference is made to the neurotransmitter dopamine, it is usually followed by the catchphrase, “the pleasure molecule” or “the reward molecule.” What all contributors to the discussions about ADHD agree on is that dopamine plays a pivotal role in the cause of the condition that affects about one in ten people at some point in their lives. There is also considerable agreement that managing dopamine levels can be an effective way to manage the symptoms of ADHD, although how to achieve this best can be a subject of some discussion.

Over the past few weeks, two articles examining managing dopamine levels from different angles crossed my desk. What I learned presents a perspective that sheds light on the need to customize solutions for people with ADHD, emphasizing the significance of managing dopamine levels due to its unique role in triggering the disorder for each person.

Understanding the role and workings of dopamine is very important when dealing with people who are living with ADHD. There is well-documented research that ties the behaviors of people who have ADHD with the levels of dopamine in their brains. Most traditional therapies rely on managing dopamine levels in one way or another by controlling how it is manufactured and consumed in the brain.

Dopamine as brain food

One article titled “Using a Dopamine Menu to Stimulate Your ADHD Brain,” published in ADDitude, draws a parallel between the human brain and one of the leading developments in modern life – the electric car. In the same way that this car has a finite power source and must stop and recharge before the battery runs out, the human body has finite dopamine reserves. These need to be replenished in step with consumption through managing dopamine levels. 

There’s also a fundamental difference between a battery-powered vehicle and a dopamine-powered brain. A car will keep going at full throttle as long as there is any power left in the battery and will shut down completely when there’s nothing left. For a person with ADHD, depletion of dopamine levels will result in altered behavior long before the wells run dry. As emphasized in a different article on ADDitude.com, “ADHD is not a difference in behavioral preference. Instead, ADHD appears to be partially attributed to a difference in how the brain is structured. What may look like behavioral choices — laziness, sloppiness, and forgetfulness — are likely due to differences in brain structure.” This results in an inability to effectively get the dopamine resources available to the locations inside the brain where they are needed. This blog will explore how dopamine is used in the two pathways most closely associated with voluntary behavior.

Redefining dopamine: The “desire molecule”  

A new way of understanding how dopamine works comes from the book “The Molecule of More” by Prof. Daniel Lieberman, clinical professor of Psychiatry and Behavioral Sciences at George Washington University. As set out in this book, dopamine is a chemical that fuels people’s desires rather than being the “reward” molecule released when a pleasurable activity has finished.

According to Dr. Lieberman, dopamine is a neurotransmitter that plays a key role in shaping everyone’s hopes and dreams. Envision life, he says, as a journey navigating between reality and the realm of possibilities. While dopamine usually stays in the background of a person’s life, it takes center stage when someone explores new paths. Apart from bringing pleasure, dopamine motivates individuals to long for what they lack, setting the groundwork for ambitions and subsequent actions. It acts as the chemical driving force behind striving towards goals, whether it’s seeking knowledge, experiences, wealth or even love.

Individuals with Attention-deficit/Hyperactivity Disorder (ADHD) often lean towards immediate gratification over long-term consequences. This inclination towards impetuous behavior arises when the pursuit of pleasure overrides decision-making processes in the brain. Those with ADHD frequently find themselves making choices that may not be beneficial but struggle to resist due to a craving for satisfaction that overrides the need to regulate dopamine levels.

The dynamic interaction between dopamine and desire reveals how this neurotransmitter impacts individuals with ADHD traits and their behaviors. The primary cause behind symptoms like hyperactivity and impulsiveness in individuals with ADHD is closely tied to their brain’s dopamine levels. Dopamine influences behaviors by fueling a person’s desire for experiences and excitement. It operates independently of functions, emotions and fear, serving as the driving force behind impulses.

The presence of dopamine explains why individuals with ADHD may engage in behaviors or make decisions that others perceive as irrational. It fuels the determination of those to make sacrifices for success and happiness, as well as the yearning for novel and stimulating experiences often linked to hyperactivity.

In summary, dopamine motivates individuals with ADHD to pursue their goals, seek out experiences and overcome challenges they encounter.

More about dopamine

A researcher in a U.K. hospital discovered dopamine in the brain in 1957. The reputation of dopamine as the “pleasure molecule” came from experiments with drug addicts. By injecting a combination of cocaine and radioactive sugar into volunteers, scientists could trace which parts of their brains were gobbling up the sugars. Participants had to report when they felt the most significant high as the cocaine took effect. The researchers observed that the highest levels of neural activity that coincided with the subjects’ reported highs occurred in the specific areas of the brain dopamine reward pathway. Dopamine activity decreased as the cocaine levels diminished and the high faded.

Most dopamine is produced in nerve cells (neurons) inside the brain, but it is also produced in small amounts in the medulla of the adrenal glands.

Dopamine is the neurotransmitter that is involved in four separate messaging pathways inside the brain. Only two of these areas are directly related to ADHD:

• The pleasure pathway (technically known as the mesolimbic pathway) connects two areas of the primitive brain (the ventral tegmental area or VTA and the nucleus accumbens or NAcc.)  Dopamine carries signals from the VTA to the NAcc as part of the reward-seeking functions of the brain. It is how your brain tells you that something is enjoyable. When it’s overactive, it can lead to the intense cravings that are underlying many addiction behaviors and that make them hard to break. For ADHD, getting the balance right here can help manage the urge to seek constant stimulation.
• The thinking pathway (also called the mesocortical pathway) is essential for cognitive (decision-making) or “thinking” functions, which happen in the working memory located in the prefrontal cortex and are exclusive to the human brain. This path helps with planning and focusing. Disruption in dopamine levels can make it hard to concentrate or make decisions. Medications for ADHD, such as amphetamines, can work by helping this pathway communicate its messages more clearly but may also increase the risk of addiction due to unintended effects in the mesolimbic pathway.

The two other pathways are the movement pathway (the nigrostriatal pathway) and the hormone control pathway (the tuberoinfundibular pathway.) They account for over 80% of all the dopamine consumption in the brain. They are involved in motor control and control of hormones produced by the pituitary gland. 

What do we know about dopamine and ADHD?

Although the relationship between dopamine and ADHD is not yet fully understood, it is believed that ADHD is linked to changes in how dopamine is produced, released, and processed in the body. This points to the critical point about managing dopamine levels highlighted in this blog. Unbalanced dopamine activity, particularly in executive functions and reward-processing areas of the brain, can affect attention and behavior control.

The main point of discussion in this article is how best to manage dopamine levels by maintaining adequate levels in the brain. The typical behaviors that are symptoms of ADHD most frequently show up when dopamine levels are depleted, so for any treatment to be effective, it must prevent swings in the levels of dopamine.

Current research proposes that ADHD is associated with a malfunctioning dopamine system in the brain rather than simply low or high levels of dopamine. This suggests that there may be abnormalities in the production, transmission, or reception of dopamine and emphasizes that looking for a way to address the symptoms of ADHD by managing the levels of dopamine is an oversimplification of a far more complex condition.

There are potential issues to consider;

• In some individuals with ADHD, there may be a density of dopamine transporters. These transporters remove dopamine from the nerve synapses, potentially reducing their availability for signaling.
• Dopamine receptors might be less responsive to the neurotransmitter, resulting in signal transmission and reduced effects.
• Certain variations in genes related to dopamine production or signaling could contribute to an increased risk of ADHD.

Many of the core symptoms of ADHD, such as inattention, hyperactivity, and impulsivity, may be linked to disruptions in the brain’s reward and motivation pathways involving dopamine.

Individuals with ADHD might engage in stimulating activities as a way to compensate for lower dopamine signaling. This can lead to behaviors that seem irrational. But they are serving as a means of seeking out new experiences, which are the source of dopamine boosts.

What are the building blocks of dopamine?

Both in the brain and adrenal glands, dopamine production starts with two essential components:

• Phenylalanine is an amino acid that can be converted to another amino acid, tyrosine, the immediate precursor for dopamine synthesis. The conversion process utilizes a specific enzyme called tyrosine hydroxylase (T.H.).
• In the brain, dopamine is produced mainly by neurons in the midbrain and hypothalamus. Feedback mechanisms and the availability of precursors tightly control the production.
• In the medulla of the adrenal glands, production is less tightly controlled than in the brain, influenced primarily by hormonal signals and stress response. The production level typically goes in step with adrenaline and noradrenaline, hormones that contribute to the fight-or-flight response.

How do we stabilize dopamine levels?

Short-term remedies

Coming back to the electric car analogy, there are ‘fast charge’ options that can quickly top up dopamine levels. These come in the form of medications that are widely prescribed for people with ADHD, which are stimulants (methylphenidates like Ritalin or Concerta and amphetamines like Adderall or Vyvanse.) The main advantage is that they act directly to boost the levels of dopamine and norepinephrine almost immediately, and the dosage can be tailored to closely match the levels of extra neurotransmitters an individual patient requires. 

On the other hand, like all drugs, they come with side effects, including appetite suppression, nausea or vomiting, dry mouth, and weight loss. More significant is the possibility of abuse or dependency. Methylphenidate and amphetamines are classified as Schedule II controlled substances by the U.S. Drug Enforcement Administration (DEA) due to their potential for abuse and dependence.

Abuse of stimulant medication comes from its ability to enhance cognitive performance, increase alertness, and induce a sense of well-being or euphoria. Especially for older teenagers who may be more prone to experimenting, there are many ways in which these drugs can be abused. They may be absorbed through inappropriate routes of administration (e.g., snorting or injecting), there can be dosage abuse by higher doses, and it’s relatively simple to obtain unprescribed doses. All of these can lead to serious health risks, such as cardiovascular issues, increased blood pressure, seizures, and psychological consequences, such as agitation, paranoia, or hallucinations. Chronic misuse can also affect growth and development.

Dependence comes from a physical or psychological reliance on a substance when a person experiences withdrawal symptoms if intake is discontinued or reduced. Stimulant medications can lead to physical dependence in some cases, as the body may adapt to the presence of the drug over time. This can result in increasing doses to achieve the same therapeutic effects or to avoid withdrawal symptoms. This can, in turn, amplify the usual adverse effects such as fatigue, depression, and disturbed sleep patterns. Psychological dependence can also grow, as individuals may develop a strong desire or craving for the medication, believing they cannot function properly without it.

Medium-term remedies

Returning to the source article in ADDitute.com, “Just like it’s hard to make really good food choices when you are already hungry, it’s tough to make good dopamine choices when you’re already low on dopamine.” The best way to achieve stable dopamine levels is to keep the supply chain of the essential ingredients that go into maintaining brain health topped up. One of the most important is omega-3 fatty acid, a polyunsaturated fatty acid (PUFA) essential for maintaining structure in the brain’s nerve cells (neurons.) The brain comprises mainly organic fats (contributing over sixty percent of its weight.) Like any living organ, the brain relies on a steady supply of the correct nutrients to maintain its structure, health, and function. The brain’s building blocks are essential polyunsaturated fatty acids (PUFAs). PUFAs are not made naturally in the body but must come from foods.

If there are not enough PUFAs being fed into the brain, it can result in a number of disorders, including:

• The degeneration of the outer shield covering individual neurons, which can disrupt communication between areas of the brain. This can affect various cognitive and motor functions.
• A reduction in serotonin production. Serotonin is another essential neurotransmitter involved in message signaling.
• The malformation of dopamine receptors located at the point at which signals pass from one nerve cell to another (nerve synapses.) This has been associated with various neurological disorders, including Parkinson’s disease, schizophrenia, as well as ADHD

The only realistic options for maintaining adequate levels of omega-3 are via a diet rich in cold seawater fish (salmon, tuna, sardines) or a dietary supplement that specifically provides the elements that go into keeping the brain healthy. One option is for fish oil capsules (krill oil, cod liver oil, or algal oil), but many people find this difficult and expensive. We can supply a cheaper and simpler option in Zoomind, which is a specially designed mixture of essential omega-3 fatty acids in the proper combination of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), together with components like l-tyrosine and phosphatidylserine that act to enhance the effectiveness of DHA and EPA. In practice, a lower dosage of omega-3 works just as well as larger doses of fish oils and other alternative supplements. As a side benefit, the overall cost of a supplement like Zoomind is far lower than buying and preparing so many ocean-fishing meals.

• DHA plays an essential role in promoting communications within the brain. It supports optimal levels of dopamine, norepinephrine, and some other neurotransmitters (serotonin and acetylcholine.)
• EPA can limit the expression of a brain chemical (cytokine) that causes inflammation, which has been closely associated with ADHD. For example, children with ADHD are more likely to suffer from other inflammatory conditions, such as asthma and atopic dermatitis.
• Phosphatidylserine is a phospholipid, a type of fat found in high amounts in the brain. It is essential in maintaining the health of neurons. It works to improve memory and cognitive capacity. 
• L-tyrosine is an essential amino acid for the production of dopamine and norepinephrine. 

Traveling the dopamine reward pathway 

The pathway responsible for releasing dopamine involves multiple areas of the brain.

The ventral tegmental area (VTA), located in the midbrain, serves as the source of dopamine in the reward pathway. It contains neurons that release dopamine when a person experiences something rewarding.

The nucleus accumbens (NAcc) is situated within the striatum (a cluster of neurons in the subcortical basal ganglia of the forebrain.) This area receives the released dopamine from the VTA. It plays a role in associating pleasure with specific stimuli and motivates a person to seek them out again.

The prefrontal cortex (PFC) controls higher-order cognitive functions, including speech formation, vision, working memory, and risk processing. It is the area of the brain that plays the most significant role in personality, control of thoughts, and actions in achieving internal goals. Based on feedback from the NAc, it processes emotions and memories associated with rewards.

Some other areas of the brain, such as the amygdala, hippocampus, and dopamine neurons, are also involved in the reward pathway. The neurons extend from the VTA to parts of the brain, including NAcc, PFC, and amygdala, establishing a network facilitating communication within the reward system.

When a person encounters something expected to bring a reward, specific neurons in the VTA region of the brain become active. These neurons release dopamine into the NAcc area, which produces feelings of pleasure and motivation. The NACC, with input from the amygdala and hippocampus, then communicates with the PFC to assess the significance of the reward and plan appropriate actions. The information processed by the PFC guides behavior, prompting the person to pursue rewarding experiences in the future.