Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood disorders and can continue into adulthood. Statistics estimate that ADHD affects 11% of children aged 4-17, 8.7% of adolescents aged 13-18, and 4.4% of adults aged 18-44. Based on data from the National Survey of Children's Health (NSCH), the median age of diagnosis is six years, and approximately one-third of people diagnosed with ADHD during childhood retain the diagnosis into adulthood. (1)

It's estimated that adult ADHD affects more than eight million adults, but many of them haven't been given a diagnosis. Studies suggest that less than 20% of adults with ADHD know they have it, and about one-quarter of those who do know are getting treatment. Adult ADHD symptoms may not be as apparent as symptoms in children, but ADHD can lead to problems, including unstable relationships, poor work and school performance, and low self-esteem. (2, 3)

An integrative medicine approach to ADHD diagnosis and treatment can help adults with ADHD regain control and improve their quality of life. This article will discuss functional medicine labs to consider that can provide valuable insight into the root causes of ADHD and steer you toward effective treatment options.

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What Is ADHD?

ADHD is a neurodevelopmental disorder that impacts the part of the brain that controls executive functioning, resulting in problems with concentration, planning, completing high-attention requiring tasks, and controlling behavior.

There are three different subclassifications of ADHD, depending on which symptoms are predominant in an individual. Because symptoms may change over time, one person may fall into these different categories throughout life. (4)

Predominantly inattentive presentation is characterized by difficulty organizing or finishing tasks, paying attention to details, or following instructions or conversations. Adults with predominantly inattentive ADHD are easily distracted, have trouble remembering appointments and keeping a schedule, and frequently lose or misplace things. (4, 5)

Predominantly hyperactive-impulsive presentation is characterized by difficulty sitting still, feelings of restlessness, and impulsivity. Adults with hyperactive-impulsive ADHD may interrupt others or speak at inappropriate times. They often feel better in active jobs and playing sports and may identify as thrill-seekers. (4, 5)

A patient is diagnosed as having a combined presentation when the symptoms of the above two types of ADHD are equally present in the person. (4)

What Causes ADHD?

No single risk factor explains ADHD. For most people with ADHD, the accumulation of genetic and environmental risk factors contributes to the disorder, most exerting their effects in the early fetal developmental and post-natal stages of life. (6)

Genetics

Many large studies confirm a genetic component to ADHD. Many genetic risk variants have been identified. Each variant has a small effect on its own, but when combined can increase the risk for ADHD. However, ADHD can occur without a family history, and not all individuals of the same family will develop ADHD. This suggests the importance of the interplay between genes and environmental factors in the development of the disorder. (6, 8)

Nutrition

A number of nutrient deficiencies are more common in people with ADHD, and evidence supports that nutrient deficiencies and poor diet can contribute to ADHD symptoms. Micronutrients of importance include vitamin D, iron, zinc, magnesium, vitamin B6, and omega-3 fatty acids. (7)

In 1975, an allergist first proposed that artificial food additives might lead to hyperactivity in children. Since then, researchers have continued to study this topic, and evidence supports that incorporating artificial food colorings and allergenic foods exacerbates ADHD symptoms. In contrast, the elimination of colorings and preservatives provides significant benefits to patients. Food additives of significant importance pertaining to ADHD include red and yellow food dyes, aspartame, monosodium glutamate, sodium benzoate, high fructose corn syrup, and nitrites.

Environmental Exposure

Exposure to harmful environmental toxins and infections has been linked to the development of ADHD. Heavy metals like lead and mercury detrimentally interfere with neural signaling, impair neural development, and worsen ADHD symptoms. Exposure to viral and bacterial pathogens in early life, such as enterovirus and Epstein-Barr virus (EBV), may cause neuroinflammation, learning disability, and hyperactivity. (7, 8)

Maternal smoking and alcohol consumption during pregnancy is another risk factor for a child to develop ADHD. Neuroimaging reveals a decrease in the brain size in those with ADHD exposed to one or both substances in utero. (8)

Stress and Trauma

Severe traumatic brain injuries have been associated with the risk of ADHD. Other factors, including preterm delivery, low birth weight, and adverse childhood events, can also increase ADHD risk and worsen the severity of ADHD symptoms. (5, 8)

Who Does ADHD Affect?

Using data from 2016-2019, the estimated number of children aged 3-17 years diagnosed with ADHD is 6 million. Boys are more likely to be diagnosed with ADHD than girls. Black and Caucasian children are more often diagnosed with ADHD than children of Hispanic and Asian descent. If a child's parents or older sibling has ADHD, their risk for developing the disorder increases by 50% and 30%, respectively. (9, 10)

ADHD Symptoms

The three primary symptoms of ADHD include inattention, impulsivity, and hyperactivity. Symptoms vary according to the type of ADHD someone has. (5)

Examples of inattentive symptoms include (8):

• Forgetfulness
• Difficulty staying on task
• Lack of focus and easy distractibility
• Struggle with organization
• Appears not to be listening when spoken to
• Fails to complete assignments and responsibilities
• Disliking tasks that require long-duration mental effort
• Losing personal belongings often

Examples of hyperactivity symptoms include (8):

• Constantly "on the go"
• Frequently fidgets
• Cannot stay seated for extended periods
• Excessive talking

Examples of impulsivity symptoms include (8):

• Frequently speaks out of turn
• Has difficulty waiting their turn in line
• Invades others' personal space
• Engagement in dangerous behaviors

Top Labs to Run on Your ADHD Patients

Functional lab testing helps evaluate for underlying contributory factors of ADHD in adults. The data retrieved from these labs assists your integrative doctor in determining the direction of care and treatment required. The following are labs to consider ordering for your adult patients with ADHD.

Organic Acids

An organic acid test (OAT) is a urine test that measures the metabolic byproducts of biochemical pathways in the body. This test can be a good screening tool; results can be used to obtain information regarding the nutrient status of vitamins, amino acids, and other essential nutrients; mitochondrial efficiency and energy production; detoxification; neurotransmitter metabolism; and intestinal dysbiosis. Based on the provider's approach, treatment may be initiated based on these results, or the provider may suggest additional testing specific to neurotransmitters, nutrient testing, and gastrointestinal assessment.

Micronutrients

Functional medicine providers often utilize micronutrient panels to measure the intracellular levels of essential vitamins, minerals, and antioxidants. Intracellular levels can better reflect a patient's long-term nutritional status of critical micronutrients and their functionality at a cellular level.

Single nutrients can also be measured if you prefer to order only part of the panel. Depending on the lab of choice, a finger stick or standard blood draw can measure Vitamin D, Omega-3s, RBC magnesium, zinc, and iron.

Optimal Reference Ranges for Micronutrients

• Vitamin D: 50-90 ng/mL
• Omega-3 Index: 8-12%
• RBC Magnesium: 5-7 mg/dL
• Plasma Zinc: 90-135 ug/dL
• Ferritin (Iron): 60-90 ng/mL

Food Sensitivities

Because sensitivities to foods and food additives can affect behavior, screening for immune reactions against specific items may be an important aspect of testing. Elevated antibody responses on these panels indicate the need for an elimination-rechallenge diet. There are several types of panels you may consider ordering:

• A food additives test measures IgA and IgG-type immune reactions against food dyes, preservatives, emulsifiers, and sugars commonly added to foods.
• Similar panels measuring IgA and IgG-immune reactions against specific foods can identify non-allergic food sensitivities contributing to leaky gut and brain.
• Food allergen panels measure IgE-mediated immune reactions against food proteins to identify true food allergies.

Gut Analysis

Intestinal inflammation, maldigestion, and dysbiosis can contribute to a leaky gut, interfere with adequate nutrient absorption, disrupt healthy neurotransmitter production, and lead to neuroinflammation. Because of this, a comprehensive assessment of gut health and function with a stool test is often warranted in patients with ADHD. The following table summarizes key biomarkers and what they indicate when elevated:

Heavy Metals

Exposure to heavy metals can be identified through blood, urine, and hair testing. Because even low levels of certain heavy metals can interfere with neurological function, very low-to-no levels of metals are desired in the body.

Urine metal testing is common among functional medicine providers. Testing urine before and after a chelation provocation can be useful to provide different information regarding exposure and total-body burden. The pre-provocation test picks up current and recent exposure, whereas a post-provocation test helps determine the level of metals stored in body tissues. (11)

Neurotransmitters

Imbalances in the neurotransmitters GABA, dopamine, and glutamate are associated with hyperactivity and ADHD. Poor gut health can detrimentally affect neurotransmitter status because most neurotransmitters are synthesized in the gut, a process dependent on a healthy gut microbiome. A comprehensive neurotransmitter profile may benefit patients with abnormal OAT and/or stool test results, or those with gastrointestinal symptoms, to better determine how they are synthesizing and metabolizing neurotransmitters.

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When to Retest Labs

Correcting underlying imbalances associated with ADHD through a functional medicine approach can take time. Once a personalized treatment plan is created, follow-up is generally recommended between 6-12 weeks later. Given the cost associated with many of these labs, practitioners often postpone re-ordering labs to monitor treatment progress until the three-to-six-month mark. As with all things related to a functional medicine approach, the frequency and interval at which labs are ordered are highly individualized, dependent upon practitioner-patient preference and the necessity for lab-based monitoring.