A dysfunctional thyroid may lead to a chemical imbalance in the brain, sometimes triggering anxiety and panic attacks.

Thyroid disorders are complex and highly individual — meaning these conditions look very different in each person.

But even with all the nuance and variation in thyroid dysfunction, anxiety disorders are notably more common in people with thyroid conditions than they are in the general population.

Anxiety frequently shows up in people with both overactive and underactive thyroid disorders. But why?

The thyroid is a small, butterfly-shaped gland located in the front of your neck.

A very important part of your endocrine system, your thyroid controls your metabolism with two primary thyroid hormones — T3 (triiodothyronine) and T4 (thyroxine).

T4 and T3 allow you to metabolize proteins, fats, and carbohydrates; regulate your mood and body weight; and maintain your body temperature, blood pressure, and heart rate.

How do we test for a thyroid condition?

We can observe thyroid function with a blood test, called a TSH test, that measures your thyroid stimulating hormone (TSH) levels. If these levels are too high or too low, it means your thyroid isn’t working correctly.

High numbers on the test actually mean your thyroid is low or underactive, and vice versa.

For instance, when your thyroid hormones are underactive — a condition called hypothyroidism — the brain’s pituitary gland will make more thyroid stimulating hormone (TSH), to prompt your thyroid to produce more thyroid hormones.

In contrast, when your thyroid levels are overactive — a condition called hyperthyroidism — the pituitary gland makes less TSH in an attempt to decrease production – so your test levels are low.

A dysfunctional thyroid may trigger a neurotransmitter imbalance which can result in anxiety and panic attacks.

In a large review of 44,388 participants, people with thyroid conditions had significantly higher levels of anxiety and depression compared to healthy people.

Anxiety can occur in both under- and overactive thyroid conditions, but it’s more common in hyperthyroidism.

In fact, anxiety affects about 60% of people with hyperthyroidism, compared to about 30% in hypothyroidism. People with an overactive thyroid also have higher rates of specific anxiety disorders, including generalized anxiety disorder (GAD), panic attacks, and agoraphobia.

Can low thyroid cause anxiety?

While less common than in hyperthyroidism, anxiety is also seen in people with hypothyroidism.

One study found that 29.4% of levothyroxine-treated women with hypothyroidism experienced anxiety, compared to 16.7% of women without a thyroid condition.

Psychiatric symptoms are frequently seen in the beginning stages of hypothyroidism. In fact, they make up about 2%-12% of the first symptoms in reported cases. These early symptoms often present as anxiety, memory lapses, progressive mental slowing, or speech deficits.

Mental health symptoms become more common as the severity of hypothyroidism increases: About 30%-40% of people with acute hypothyroidism have an anxiety disorder.

Anxiety symptoms in thyroid disorders may include the following:

  • racing heart
  • sleeping difficulties
  • irritability
  • poor concentration
  • sweating
  • nervousness
  • tremors/shaking
  • weight loss

The causes of anxiety symptoms in thyroid disease depends on whether a person has hyperthyroidism or hypothyroidism.

Hyperthyroidism essentially “speeds up” your body’s metabolism. This causes your entire sympathetic nervous system to become more active, leading to feelings of anxiety. In fact, your whole body could feel like it’s shaking and going into overdrive.

In contrast, hypothyroidism leads to an imbalance of neurotransmitters, such as serotonin. Although this imbalance often leads to feelings of depression, anxiety is also a common symptom.

Thyroid dysfunction — both overactive and underactive — can lead to various mental health symptoms ranging from mild depression to anxiety to psychosis.

Depression is particularly common in people with thyroid conditions. Research has shown that many people with depression have significantly abnormal levels of T3, T4, and thyroid-stimulating hormone (TSH).

Research suggests that about 20.5% of individuals with hypothyroidism have depression. People with underactive thyroid also frequently exhibit symptoms of cognitive dysfunction, apathy, and psychomotor slowing. In severe forms of hypothyroidism, clinical symptoms may look like melancholic depression and even dementia.

Depending on the research, prevalence of depressive disorders in hyperthyroidism may range anywhere from 31%-69%.

Even mild cases of thyroid dysfunction can lead to depression.

Thyroid hormones carry out very important actions in the brain. Any dysfunction in this process can lead to a variety of psychiatric symptoms.

Anxiety disorders can occur in both overactive and underactive thyroid conditions.

If you have symptoms of anxiety, consider getting your thyroid levels checked out. At least this could rule out a thyroid condition before you begin other types of treatment.

If you already know you have a thyroid condition, routine screening and mental health care is important to keep your symptoms in check.