When most people think about thyroid-related anxiety, they think about hyperthyroidism, a condition where the thyroid produces too much hormone. That association makes sense. Excess thyroid hormone can leave the body feeling like it is constantly pressing on the accelerator, producing symptoms such as a racing heart, nervousness, tremors, heat intolerance, and difficulty sleeping. [1]
What receives far less attention is that hypothyroidism, or low thyroid hormone activity, can also be associated with anxiety, with some estimates showing that 30-40% of those with hypothyroidism also suffer with anxiety. [2] At first glance, this seems contradictory. Hypothyroidism is typically linked with fatigue, slowed thinking, constipation, cold intolerance, dry skin, weight gain, and low mood. Anxiety seems like it belongs on the opposite end of the spectrum. [3]
Yet the relationship between thyroid function and emotional health is far more complex than simply "high thyroid equals anxiety" and "low thyroid equals depression." The thyroid helps regulate many systems that influence how we think, feel, and respond to stress. When thyroid hormone activity declines, emotional resilience may decline alongside it in some individuals.
Can Hypothyroidism Cause Anxiety?
The short answer is yes, it may contribute to anxiety symptoms in some people, but it is rarely the only explanation. Rather than saying hypothyroidism directly causes anxiety in everyone, it is more accurate to say that low thyroid function may influence the biological systems that support emotional regulation, stress tolerance, sleep, and cognitive function. [2][4][5]
Research has shown that anxiety symptoms are common among people living with hypothyroidism. [2] While this does not prove that thyroid dysfunction is the sole cause of anxiety, it reinforces what many clinicians observe in practice. Emotional symptoms often accompany the physical changes associated with reduced thyroid hormone activity.
This distinction is important because anxiety is rarely caused by a single factor. Genetics, life stress, sleep quality, medical conditions, nutrition, medications, and psychological health all play a role. Thyroid function simply represents one important piece of that larger picture.
The Thyroid Does Much More Than Control Metabolism
Most people learn that the thyroid regulates metabolism. While that is true, metabolism is only one part of its influence. Thyroid hormones help support normal function throughout the brain and nervous system. They influence neurotransmitter signaling, cellular energy production, brain development, and the body's response to physical and emotional stress. [2][6]
Because every brain cell depends on energy to function efficiently, changes in thyroid hormone activity may influence how well these systems communicate with one another. This helps explain why thyroid dysfunction may affect more than physical symptoms. It may also influence concentration, memory, motivation, emotional regulation, and overall resilience.
Why Might Low Thyroid Function Affect Anxiety?
There is likely no single explanation. Instead, several mechanisms may work together.
Reduced Energy Can Lower Stress Resilience
One of the defining features of hypothyroidism is reduced cellular energy production. Many people experience overwhelming fatigue, even after adequate sleep. [7] Daily tasks may require significantly more effort than before, leaving little reserve for managing everyday stress.
When the body is already operating with limited energy, challenges that once felt manageable may begin to feel overwhelming. Small stressors may trigger disproportionately large emotional responses because the body's ability to adapt has been reduced.
Rather than anxiety arising independently, it may develop as part of a broader picture of decreased physiological resilience.
Brain Signaling May Change
Thyroid hormones interact with several neurotransmitter systems involved in mood regulation. Scientists have long recognized connections between thyroid hormone activity and serotonin signaling, among other pathways involved in emotional health. [2] While researchers continue to investigate these relationships, they provide a biologically plausible explanation for why thyroid dysfunction may influence anxiety and mood in some individuals.
This does not mean everyone with anxiety has a thyroid disorder. Instead, it highlights why thyroid health deserves consideration when anxiety develops alongside other symptoms suggestive of hypothyroidism.
Sleep Quality Often Declines
Sleep and anxiety have a bidirectional relationship. Poor sleep can increase anxiety, while anxiety itself can make sleep more difficult. [8] People with hypothyroidism frequently report feeling exhausted during the day while still experiencing unrefreshing sleep. [7] Over time, disrupted sleep may further reduce emotional resilience, making it more difficult to regulate stress and maintain stable mood.
When fatigue, sleep disruption, and thyroid dysfunction occur together, anxiety symptoms may become even more noticeable.
Looking at the Whole Symptom Pattern
One of the biggest challenges with hypothyroidism is that many of its symptoms develop gradually. Individuals may adapt to feeling tired, mentally sluggish, or emotionally different without realizing that multiple symptoms share a common physiological contributor.
If anxiety occurs alongside symptoms such as:
- Persistent fatigue
- Cold intolerance
- Constipation
- Dry skin
- Weight gain
- Brain fog
- Depressed mood
- Menstrual changes
- A personal or family history of autoimmune thyroid disease
then thyroid health may deserve further evaluation.
No single symptom confirms hypothyroidism, and no symptom should be viewed by itself. Instead, clinicians look for patterns that suggest thyroid hormone activity may be contributing to the overall clinical picture.
Three Ways Hypothyroidism and Anxiety May Be Connected
The relationship between hypothyroidism and anxiety does not look the same for everyone. There are several possible patterns.
Anxiety May Develop Because of Hypothyroid Symptoms
Imagine feeling exhausted every day despite sleeping enough. Your concentration declines. Your memory feels unreliable. Simple tasks become more difficult. You gain weight despite making healthy choices. You no longer feel like yourself.
It is understandable that many people begin worrying about what is happening to their health, work performance, or quality of life. In these situations, anxiety may arise as a natural emotional response to persistent physical symptoms.
Low Thyroid Function May Lower Stress Tolerance
Another possibility is that reduced thyroid hormone activity affects the biological systems that help people adapt to stress. [5] When neurotransmitter signaling, sleep quality, and cellular energy production are all operating below their usual capacity, the brain may have fewer resources available for managing everyday challenges.
As a result, ordinary stressors may begin to feel much more difficult than they once did.
Anxiety May Be an Independent Condition
Finally, thyroid disease and anxiety may simply coexist. Some individuals have generalized anxiety disorder, panic disorder, trauma-related anxiety, or depression with anxious distress regardless of thyroid status.
Recognizing this possibility is equally important. Not every emotional symptom can or should be explained by thyroid function alone. The goal is to identify every contributing factor rather than assuming there is only one.
An Important Lesson From Medical History
The connection between thyroid function and mental health is not a new discovery. Long before modern laboratory testing became available, physicians observed that people with severe hypothyroidism often experienced significant changes in mood, thinking, and behavior. [9][10]
Historical descriptions of severe hypothyroidism, once referred to as myxedema, included reports of depression, cognitive slowing, paranoia, psychosis, and other psychiatric symptoms that sometimes improved after thyroid hormone deficiency was corrected. [11]
Modern medicine has greatly improved the diagnosis and treatment of hypothyroidism, making these severe presentations much less common. Even so, this history reminds us that thyroid hormones influence far more than metabolism. They also play an essential role in healthy brain function.
When Should Thyroid Testing Be Considered?
Because anxiety has many potential causes, thyroid testing is not necessary for every individual experiencing stress or worry.
However, evaluation may be appropriate when anxiety is:
- New or unexplained
- Becoming progressively worse
- Resistant to appropriate treatment
- Accompanied by classic symptoms of hypothyroidism
- Present alongside a history of thyroid disease or autoimmune conditions
Clinical guidelines also recommend considering thyroid function testing in people experiencing depression or unexplained anxiety.
The purpose of testing is not to attribute every emotional symptom to the thyroid. Rather, it is to avoid overlooking a potentially treatable physiological contributor.
The Bottom Line
Anxiety is often viewed as a hallmark of an overactive thyroid, but that tells only part of the story.
Low thyroid function may also influence emotional well-being by affecting brain signaling, cellular energy production, sleep quality, and the body's ability to adapt to stress. For some people, anxiety develops as a consequence of living with persistent hypothyroid symptoms. For others, reduced thyroid function may lower overall stress resilience. In still others, anxiety and thyroid disease simply coexist.
Understanding these possibilities allows for a more thoughtful and individualized approach to care. If anxiety appears alongside fatigue, brain fog, constipation, cold intolerance, dry skin, weight gain, or other classic signs of hypothyroidism, discussing thyroid evaluation with a healthcare practitioner may be an important next step.
The encouraging news is that emotional health and physical health are deeply interconnected. Looking beyond symptoms in isolation can help uncover contributing factors that might otherwise be missed and move you closer to feeling like yourself again.
Disclaimer:
The information provided is for educational purposes only. Consult your physician or healthcare practitioner if you have specific questions before instituting any changes in your daily lifestyle including changes in diet, exercise, and supplement use.
Allison Sayre, MSN, WHNP is a board-certified women’s health nurse practitioner with advanced expertise in hormonal health, integrative gynecology, and patient-centered care across the lifespan. She holds a Master of Science in Nursing and has served as both a clinical provider and educator in functional and conventional women’s health settings. At ARG, Allison contributes to medical education, clinical protocol development, and strategic content that supports the evolving needs of women's healthcare practitioners.
