While symptoms more commonly associated with thyroid dysfunction include weight changes, energy levels, or temperature intolerance, thyroid function is also closely tied to mental health and can present as anxiety, depression, or mood changes. The thyroid has an impact on many different physiological systems, including heart rate and blood pressure, cognitive function, and even blood flow to the brain.

Some research has referred to depression as “brain hypothyroidism” to bring to light the close connection between thyroid function and mental health. A root cause medicine approach can explore the intricate connection between the thyroid and mental health, using a thorough patient history and functional medicine lab testing to explore how imbalances in thyroid hormones may impact mental well-being and to create a subsequent personalized care plan to support overall health.  

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Overview of Thyroid Function

The production and regulation of thyroid hormones begins in the brain. When part of the brain called the hypothalamus detects low levels of thyroid hormones, it produces a hormone called thyroid-releasing hormone (TRH). TRH signals the pituitary gland, another part of the brain, to release thyroid stimulating hormone or TSH. TSH then signals the thyroid gland to make thyroxine (T4) and T3, in roughly a 90/10 ratio. Peripheral enzymes called deiodinases convert T4 into the active T3 as needed. The hypothalamus will stop producing TRH when thyroid hormone balance has been restored or if it detects too much thyroid hormone in the circulation. 

Once thyroid hormones are produced, they play a role in a variety of metabolic processes throughout the body. Thyroid hormones are required for normal growth and development as well as metabolism regulation, modulation of insulin sensitivity, and metabolism of cholesterol and carbohydrates. Thyroid hormone levels impact your blood pressure, body temperature, menstrual cycle health, hormone balance, and weight management.

When too much thyroid hormone is produced, it’s referred to as hyperthyroidism. The excess amount of thyroid hormones can cause different metabolic processes in the body to “speed up,” leading to symptoms such as weight loss, irregular heartbeat, fatigue, trouble sleeping, hot flashes and heat sensitivity, anxiety, or changes in menstrual cycle health.  

On the opposite side of the spectrum, hypothyroidism refers to a physiological state in which not enough thyroid hormones (T4 and T3) are produced. Hypothyroidism encompasses an array of symptoms that reflect a slowing down in metabolism, including fatigue, weight gain, depression, constipation, brain fog, hair thinning, intolerance to colds, and fluid retention, amongst others. Long-term, untreated hypothyroidism may also result in cardiovascular and neurological symptoms, including increased cholesterol and numbness or tingling in the extremities.  

Thyroid Dysfunction and Mental Health Correlation

Both hypothyroidism and hyperthyroidism have been linked to various mental health issues, including anxiety, depression, and cognitive impairment. Thyroid hormones bind to specific receptors in the brain, modulating neuronal plasticity and other brain functions. In those with generalized anxiety disorders and panic disorders, the likelihood of thyroid dysfunction is also higher, underlining the relationship between thyroid health and mental health.  

Hyperthyroidism in particular has been linked to increased risk of anxiety and even panic attacks, with symptoms often diminishing once proper thyroid function is restored. Studies have demonstrated that up to 60% of patients with hyperthyroidism show signs of a psychiatric disorder, underlining the strong link between thyroid function and mental health.

Perhaps one of the most well-established relationships between thyroid function and mental health is the link between hypothyroidism and depression.  Hypothyroidism is one of the leading causes of treatment-resistant depression and has also been linked to forgetfulness, fatigue, mental slowness, and unpredictable mood changes. A higher prevalence of depression and anxiety has been found in the subclinical hypothyroid population as well, indicating the thyroid-mental health link may be impacted early on in the progression of thyroid dysfunction. 

Studies have found a connection between the hypothalamic-pituitary-thyroid (HPT) axis and neurotransmitters like serotonin as a potential mechanism for the link between thyroid health and depression. Some researchers even use the term “brain hypothyroidism” when describing major depressive disorder, due to the important impact of the thyroid on cognitive function and mood.

Autoimmune thyroid conditions are also linked to mental health dysfunction.  Hashimoto’s thyroiditis is associated with a higher risk of depression, while higher rates of both anxiety and depressive symptoms have been found in patients with untreated Graves’ disease when compared to their healthy peers. There are a few mechanisms by which autoimmune thyroid disease may impact mental health outside of thyroid hormone level changes, including cross-reactivity with brain and central nervous system tissues as well as altering blood flow to different areas of the brain, as thyroid dysfunction can impact the brain’s vasculature.  

A Root Cause Medicine Approach to Diagnosing Thyroid Conditions

Ultimately, screening the thyroid with TSH alone may miss up to 7% of patients with overt thyroid dysfunction. Root cause medicine practitioners will often do a comprehensive evaluation of the thyroid early on with patients, to not miss early signs of thyroid dysfunction. Looking at TSH, peripheral thyroid hormones, and thyroid antibodies helps practitioners gain insight into the downstream function of the thyroid as well as potential autoimmune mechanisms at play underlying a patient’s symptoms. This is not typically the case in a conventional approach to thyroid management, which follows the thyroid function cascade of ordering TSH first, then free T4 if necessary.  

The Comprehensive Thyroid Panel by Access Medical Labs allows for deeper insight into other hormones, immune-thyroid relationships, and communication between thyroid biomarkers via the HPT axis. The panel includes TSH, free T4, free T3, reverse T3, thyroglobulin antibodies, and thyroid peroxidase antibodies. If Graves’ disease is suspected, Thyroid Stimulating Immunoglobulins (TSI) can also be ordered through Access Medical Labs.

A comprehensive thyroid panel can also help root cause medicine practitioners assess subclinical thyroid issues, which can affect up to 8% of the population and are more common in women.  Subclinical hypothyroidism refers to a state where thyroxine (T4) is in the normal range, but TSH levels are mildly elevated and have been associated with a higher risk of depression.

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The Causes of Thyroid Dysfunction

Several different root causes can lead to thyroid dysfunction, including autoimmune reactions, nutritional deficiencies, stress, and environmental toxins. Practitioners will consider all of these root causes when assessing a patient with signs and symptoms of thyroid dysfunction or mental health symptoms to personalize an effective treatment plan.

When it comes to cases of autoimmune thyroiditis, thyroid autoantibodies are often detectable in patients years before they show clinical signs and symptoms of thyroid disease, meaning early screening could be beneficial. In autoimmunity, the body’s immune system produces antibodies against its own tissues, causing inflammation and destruction of the tissue. 

‍Hashimoto’s thyroiditis involves the production of antibodies against the thyroid peroxidase enzyme and thyroglobulin, impacting the thyroid’s ability to make thyroid hormones over time. With the resultant decrease in thyroid hormone, patients typically begin to experience symptoms of hypothyroidism, including depression and brain fog, that can impact their mental health and cognitive function.  

Nutritional deficiencies, especially concerning minerals important for thyroid function, can also be a root cause of thyroid problems.  Iodine deficiency is the most common cause of hypothyroidism worldwide, as iodine is essential for the production of T4 and T3. For some individuals, intake of goitrogen-containing foods, such as broccoli and other cruciferous vegetables, soy, and cassava, may also inhibit the uptake of iodine by the thyroid gland, though large quantities of these foods typically need to be consumed for consumption to be problematic. It should be noted that cooking the aforementioned foods helps alleviate the potential problem of goitrogen exposure. Iron deficiencies are also associated with hypothyroidism, as iron also plays a role in thyroid hormone production.  

Selenium is another mineral important for thyroid function, playing roles in thyroid hormone production as well as regulation of thyroid hormone levels. Selenium deficiency has been associated with the development of thyroid autoimmunity. Adequate zinc intake is also important for thyroid health. In addition to playing a role in thyroid hormone production, zinc deficiencies increase susceptibility to autoimmune disease, and zinc supplementation has been well-studied with beneficial effects for thyroid disorders. In addition to micronutrients, protein intake has also been studied for its importance in optimal thyroid health.  

Low protein intake has been linked to a higher risk of thyroid disorders and problems with HPT axis regulation. These various nutritional deficiencies can impact how well the thyroid can function on a basic metabolic level, putting individuals who are not meeting their nutritional needs at higher risk of thyroid dysfunction and accompanying mental health symptoms.

Stress is also a key factor that can impact thyroid health. Ongoing stress is a key component of autoimmune disease development, and chronic stress may increase the risk of developing Hashimoto’s or Graves’ disease. It’s well-known that the hypothalamic-pituitary-adrenal (HPA) and HPT axes are closely connected, with high cortisol levels signaling the thyroid to slow down the production of thyroid hormone as well as inhibit the conversion of T4 to T3. Chronic stress also has been linked independently to anxiety, depression, and other mental health dysfunctions, and its simultaneous impact on the thyroid may further exacerbate symptoms.  

Another root cause for thyroid dysfunction that may often be overlooked is exposure to environmental toxins. Exposure to radiation, including medical radiation, is one environmental factor to consider, particularly for cases of autoimmune thyroid disease. Contamination of water with goitrogens may be a factor in some parts of the world, while exposure to various chemicals has been documented to disrupt thyroid function. These chemicals include halogenated organochlorines, pesticides, PCBs, and PDEs. Chronic viral infections may also play a role in developing thyroid issues.  

Integrative Treatment Approaches

Root cause medicine practitioners use integrative treatment strategies to manage thyroid dysfunction and improve mental health outcomes in patients that may encompass dietary interventions, supplementation, detoxification, and stress reduction techniques. These strategies support root-cause healing and are personalized based on a patient’s needs. 

An anti-inflammatory, nutrient-dense diet such as the Mediterranean diet can be a great starting place for many thyroid patients, while a Paleo or autoimmune-Paleo diet is another example of a whole food diet to support optimal thyroid function. Additionally, the Mediterranean diet has been studied for its beneficial effects on symptoms of depression.  Evidence currently suggests that an anti-inflammatory diet that emphasizes micronutrient intake of selenium, zinc, iodine, and iron can help support thyroid health in those dealing with thyroid conditions. 

Nutrition to support the gut microbiome is also helpful, as the gut not only plays a role in nutrient absorption but is also often affected in cases of autoimmunity. Limiting sugar and processed foods, incorporating lean meats and fresh, whole fruits and vegetables, and including gut-healing foods such as bone broth, fermented foods, and prebiotic fibers are all strategies that can be used to create a personalized dietary plan to optimize thyroid function and support mental health.  

Including specific food sources and supplements of appropriate thyroid-supporting minerals, as determined by micronutrient testing, can also help create a personalized health plan for each thyroid patient. Zinc not only is essential for thyroid function with its role in deiodinase enzyme activity but deficiencies have also been linked to depression and mental health dysfunction. Iodine is also an important mineral to emphasize due to its role in thyroid hormone production and can be addressed simply by adding iodized salt into the diet. Last, selenium intake has been found to help reduce antibody levels in both Hashimoto’s and Graves’ disease.

Detoxification support is another important component of a root cause medicine approach to support thyroid function and mental health. Supporting detoxification can improve mental clarity, and can help support the body’s ability to metabolize and eliminate environmental pollutants that patients come into contact with regularly that may negatively impact thyroid health.

Last, stress management is essential for proper thyroid and hormone function as well as mental well-being in general. Chronic stress can negatively impact the body’s ability to produce and regulate thyroid hormones, and may also increase mental health symptoms like anxiety or depression. Mindfulness practices, regular exercise, and breathwork are all techniques patients can help reduce and manage their stress and support optimal thyroid health. 

Navigating Challenges and Patient Education

One of the biggest challenges faced in diagnosing and treating thyroid-related mental health issues is that symptoms like anxiety, depression, or changes in cognitive function can be attributable to dysfunction in many different physiological systems. This is why it’s so important for practitioners to do a comprehensive intake and use functional medicine lab work strategically to identify root causes, so a treatment plan that addresses the foundational imbalance can be created.

It might be challenging for patients to understand that their anxiety or depression is stemming from a thyroid issue, so patient education and encouraging patients to take an active role in their care plan is essential. Having patients actively play a role in goal setting and making decisions related to their care, with guidance and education provided by the practitioner, can set root cause medicine apart in terms of patient satisfaction and efficacy of care long-term. 

Additionally, patients may need a bigger care team to fully support their healing when they are faced with thyroid-related mental health issues. Co-management with therapists, endocrinologists, or other specialists may be needed to ensure each patient is fully supported while on their healing journey.

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Key Takeaways

Thyroid dysfunction can present in a variety of ways, one of which is mental health changes and cognitive dysfunction. The thyroid is an essential component of brain function and mental health, and patients with thyroid dysfunction are at a higher risk of anxiety, depression, brain fog, and other symptoms.

A root cause medicine approach to patient health can educate and empower patients to understand the intricate connection between their thyroid and mental health and help them play an active role in supporting their overall well-being.