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Is There a Link Between Thyroid Disease and ADD/ADHD?

Is There a Link Between Thyroid Disease and ADD/ADHD?

Awareness of Attention Deficit Disorder (ADD) and Attention Deficit Hyperactivity Disorder (ADHD) has increased over the past few years. This attention has helped produce more research opportunities and encouraged greater investigation into ADD/ADHD and similar disorders. However, despite these increased efforts there are still many mysteries surrounding ADD/ADHD.

One critically important aspect of ADD/ADHD yet to be fully explored is its causal factors. But current research suggests that the thyroid may play an important role in ADD/ADHD development. As such, understanding the relationship between the thyroid and ADD/ADHD may be critical in the prevention and treatment of common behavioral disorders.

What is the Thyroid?

The thyroid is a walnut-sized gland located near the front of the neck that is charged with regulating numerous bodily functions through the production of various hormones. Because of its high degree of influence, disruption of the thyroid can result in widespread bodily dysfunction. Some areas most prominently impacted by poor thyroid function include metabolism, sleep quality, weight regulation, and neurological and cognitive ability. The most common form of thyroid dysfunction, effecting an estimated 10 million Americans, is a condition known as hypothyroidism.

Learn more about the thyroid here.

What is Hypothyroidism?

Hypothyroidism is a condition wherein the body does not get the requisite amount of thyroid hormone to maintain healthy bodily function. Hypothyroidism may be caused by a variety of factors including poor hormone synthesis, slow thyroid hormone conversion, disrupted hormone transport and receptivity, and/or nutrient deficiencies. As thyroid function declines so too do thyroid hormone values. As regulators of virtually every cell and tissue in the body, a decline in thyroid hormone levels typically cause the entire body to slow down. Such a decline in bodily function can have far-reaching effects on overall wellness and may even contribute to the development of neurological issues like ADD/ADHD.

What is ADD/ADHD?

ADD and ADHD are behavioral disorders that impede the individual’s ability to focus, retain information, and interact with others. These skills are critical not only for early development but can also impact the professional and personal lives of adults.

ADD/ADHD stems from a lack of essential neurotransmitters that facilitate healthy communication within the brain. Without an adequate supply of these chemical messengers, the frontal region of the brain struggles to convey information. This disrupts higher brain function and cognitive ability, leading to symptoms such as irritability, difficulty focusing, and hyperactivity.

The occurrence rates of ADD/ADHD appear to have had a notable increase in recent years. Studies show that the rates of diagnosis for ADD/ADHD increased by 42 percent between the years 2003 and 2011. Current estimates show that nearly 11 percent of children in America are diagnosed with ADHD. Although research has not yet found a definitive reason for the increase in ADD/ADHD diagnosis, some experts believe it may be associated with the growing occurrence of thyroid disease.  

The Links Between Hypothyroidism and ADD/ADHD

It is well documented that thyroid disease encourages the development of many different chronic illnesses. Recent studies suggest that thyroid issues may even contribute to the occurrence of ADD/ADHD.

One study found that individuals who are resistant to thyroid hormones, a common component of hypothyroidism, have a much greater risk of developing ADHD. Research conducted at the University of Maryland School of Medicine expands on these findings. The Maryland researchers found that higher concentrations of thyroid hormones, specifically T3 and T4, had a positive correlation with symptoms of ADD/ADHD such as hyperactivity and impulsivity. The increased values of T3 and T4 did not correlate to symptoms relating to inattention. But this data still suggests a relationship between thyroid function and the occurrence of ADD/ADHD.

Other studies have found that poor thyroid function can disrupt and delay cell signaling to the brain that may contribute to ADD/ADHD. Jumbling of neurological messages caused by inhibited thyroid activity can lead to the development or worsening of ADHD symptoms. Additionally, thyroid dysfunction and ADHD that interrupts brain activity has been shown to delay human development and functionality. Therefore, those suffering from hypothyroidism and/or ADD/ADHD are more likely to struggle with social interaction, workplace success, and other important aspects of life.

Research also suggests that thyroid disease in pregnant women may determine the occurrence of ADD/ADHD in their offspring. Multiple studies have found that pregnant women exhibiting markers of autoimmune thyroid disease such as elevated thyroid antibodies, irregular TSH values, and depressed levels of T4, are more likely to birth children with behavioral disorders like ADD/ADHD. This association between maternal thyroid function and the occurrence of behavioral issues in their offspring exemplifies the importance of monitoring and supporting thyroid function during pregnancy.

Symptoms of Thyroid Dysfunction and ADD/ADHD

Hypothyroidism can disrupt virtually any system in the body including the brain. As hypothyroidism progresses neurological issues that mirror those associated with ADD/ADHD may appear. This can make diagnosis difficult as doctors may simply diagnose the issue as ADD/ADHD without considering possible thyroid malfunction. If an existing thyroid condition is overlooked and goes untreated, it is highly likely that ADD/ADHD-like symptoms will remain and potentially worsen.

Some of the symptoms associated with both hypothyroidism and ADD/ADHD include:

  • Brain fog
  • Depression
  • Difficulty focusing
  • Fatigue
  • Memory issues
  • Poor sleep quality
  • Weight gain
  • Loss of motivation

Further study is required to confirm the implications of the symptom correlation between these two conditions. However, as discussed above, initial findings strongly suggest that poor thyroid function plays a role in the development and/or continuation of ADD/ADHD symptoms.

Support Your Thyroid to Combat ADD/ADHD

At first glance it may not seem as though the thyroid and behavioral disorders such as ADD/ADHD have any significant relation. However, recent and continuing research suggests that thyroid function may actually have a great deal of influence over the development and continuation of ADD/ADHD and its symptoms. Although additional research must be done to confirm these findings and fully identify the influencing mechanisms, our current understanding indicates that optimizing thyroid function may do a great deal of good in preventing and alleviating ADD/ADHD. If you are or if someone you know is suffering from ADD/ADHD symptoms, be sure to talk to your doctor about getting a thorough thyroid exam and ask about improving thyroid function.


1. Álvarez‐Pedrerol, M. et al. “TSH concentration within the normal range is associated with cognitive function and ADHD symptoms in healthy preschoolers.” Clinical Endocrinology, 2007, 66(6), 890-898.
2. Porterfield, S P. “Thyroidal dysfunction and environmental chemicals–potential impact on brain development.” Environmental health perspectives vol. 108 Suppl 3,Suppl 3 (2000): 433-8.
3. University of Maryland at Baltimore. “Hyperactivity Linked To Thyroid Hormones.” Science Daily.
4. Kirk Gair, DC, IDE. “Hypothyroidism & ADD/ADHD: What You Must Know As A Parent To Protect Your Child.” Hypothyroid Mom.

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