Hypothyroidism is a common thyroid condition in which the thyroid gland does not produce enough thyroid hormones. This can impact mental well-being.

Psychiatric symptoms like low mood, memory problems, and extreme fatigue are common among people with hypothyroidism.

This article discusses the link between hypothyroidism and psychiatric symptoms, including signs to look for, and how treatment of hypothyroidism can help.

What Causes Psychiatric Symptoms?

Psychiatric symptoms include a variety of emotions, thoughts, and behaviors that are tied to mental health challenges.

Just as there are many causes of mental illness, there are a multitude of reasons why someone might experience psychiatric symptoms.

What Does “Psychiatric” Mean?

While “psychiatric” is sometimes associated with serious mental illnesses, the word simply refers to characteristics of mental illness and does not necessarily mean a mental illness is present. 

Causes can range from:

  • Genetics and family historyStressful life experiences, including trauma in childhoodChemical imbalances in the brain

While psychiatric symptoms are often caused by mental illnesses, conditions within other parts of the body, outside the mind, may be an underlying cause.

Hypothyroidism is one of these conditions. Thyroid hormones affect many areas and functions of the body, including the brain. The National Institutes of Health (NIH) estimates that 5% of Americans have hypothyroidism.

Hypothyroidism Psychiatric Symptoms

Though it is not intuitive that thyroid hormones, which come from the thyroid gland in the throat, affect the brain, psychiatric symptoms are frequent symptoms of hypothyroidism. Psychiatric symptoms associated with hypothyroidism include: 

  • Fatigue, including issues with sleeping and feeling very tiredCognitive issues, such as memory problems and slow thinkingLow mood or depressionAnxiety

In terms of cognitive issues, studies have shown that hypothyroidism affects brain functioning in several ways, including:

  • Decreasing concentrationImpairing psychomotor functioningAffecting memory (the most commonly affected mental function)

Depression and Hypothyroidism

The link between depression and hypothyroidism is well established.

While depression as a mental illness affects mood and cognition, so can low thyroid hormone levels. Testing for thyroid hormone levels is a way to differentiate depression from other health conditions. Some estimates show as many as 60% of people with hypothyroidism also experience depression.

Anxiety and Hypothyroidism

There is less consensus on the strength of the association between anxiety and hypothyroidism. Nonetheless, several studies do point to a connection between hypothyroidism and anxiety. For example, a cross-sectional study noted that 63% of people with hypothyroidism may also experience anxiety, but other studies show a much lower prevalence.

Variations

Research suggests that psychiatric symptoms may differ by the level of hypothyroidism.

For example, one meta-analysis concluded that overt hypothyroidism (when both the thyroid-stimulating hormone (TSH) and thyroid hormones are at abnormal levels) is associated with significant decreases in mood and cognitive function but only subtly so, if at all, for subclinical hypothyroidism (defined by abnormal TSH levels only). This suggests that more severe hypothyroidism is more likely to lead to psychiatric symptoms. 

Age may affect the presence of psychiatric symptoms. One study found that subclinical hypothyroidism was associated with depression in younger patients (those under 60 years old), but not in older ones.

The authors note that these results conflict with other studies showing that subclinical hypothyroidism is associated with more risk of cognitive issues and depression in older adults. More research is needed into how the level of hypothyroidism, knowledge about one’s diagnosis, and age play a role in the experience of psychiatric symptoms. 

Besides the severity of hypothyroidism and age, another contributing factor to psychiatric symptoms in hypothyroidism is that symptoms may be more common among people who know they have hypothyroidism.

In other words, people who know they have hypothyroidism may be more aware of psychiatric symptoms because they know they could be caused by hypothyroidism. For example, if you know you have hypothyroidism and know that it has been linked to mental health symptoms like depressed mood, then you may be more likely to report psychiatric symptoms. 

More research is needed on how knowledge of hypothyroidism status and its potential to lead to psychiatric symptoms impacts the presence of psychiatric symptoms. However, there is abundant research that shows that issues with thyroid functioning do in fact impact mood and cognition.

Given that some hypothyroidism psychiatric symptoms often look the same as those of depression, hypothyroidism may be overlooked and misdiagnosed as depression. Furthermore, knowing one has hypothyroidism and that it can lead to low mood may also impact their experience of depression. The cause-and-effect relationship can be complicated. However, there are several other nonpsychiatric symptoms of hypothyroidism that can help determine if that may be the cause of psychiatric symptoms.

Other Hypothyroidism Symptoms

Besides psychiatric symptoms, other symptoms of hypothyroidism include:

  • Reduced metabolic function, which may show up as weight gain, constipation, or muscle crampsBeing extra sensitive to coldHair, nail, and skin changes, including hair loss or thinning hairSexual and reproductive issues, such as irregular periods or heavy bleeding

If left untreated, hypothyroidism may lead to myxedema, but this is rare. Symptoms may include:

  • Low body temperatureLow blood pressureSlowed breathing

Diagnosis of hypothyroidism, including myxedema, is usually done with labs that test for thyroid hormone levels and may include blood content as well.

Treating Psychiatric Symptoms

Treatment for psychiatric symptoms of hypothyroidism focuses on treating the underlying thyroid issues. The standard treatment for hypothyroidism is a medication called levothyroxine (T4), but may also include a combination of levothyroxine and liothyronine (T3). These medications help stimulate the underactive thyroid so that it produces normal thyroid hormones. This, in turn, helps maintain healthy thyroid hormone levels for the brain, which will help ensure improved psychological function.

If standard thyroid treatments do not help with psychiatric symptoms, there may be an underlying mental health condition. If that’s the case, treatment will focus on improving mental well-being. For example, if depressive symptoms persist in someone treated for hypothyroidism, they may be referred to treatment for depression. Mental health challenges are treatable. They include medication, therapy, or a combination of both.

How to Get Help

If you are experiencing psychiatric symptoms such as depression, cognitive issues, or severe fatigue, it is best to speak with your healthcare provider. After listening to your experiences with psychiatric symptoms, your provider may test for thyroid problems to see if hypothyroidism is present. Such tests are sometimes the first step to determine if psychiatric symptoms are a result of hypothyroidism since hypothyroidism and mental health issues like depression are well established.

If your thyroid hormone levels check out as normal, your healthcare provider can guide you through next steps to improving your mental well-being.

Summary

Psychiatric symptoms, including depression and memory problems, are common among people with hypothyroidism. Diagnosing hypothyroidism may be the first step in treating psychiatric symptoms as hypothyroidism treatment may improve mental health support may be appropriate to treat underlying issues of mental well-being.

A Word From Verywell

It is not uncommon to feel down, tired, or forgetful, even on a normal day. There are so many reasons why these feelings surface. However, hypothyroidism is common and so are psychiatric symptoms among people with hypothyroidism.

Testing for hypothyroidism is straightforward and often starts with a simple blood draw at your healthcare provider’s office. If you learn you have hypothyroidism, do not fear. It is treatable. And if it turns out that you don’t have hypothyroidism, your provider will evaluate you further to determine the cause and treatment of your changes in mood and cognition.

Frequently Asked Questions

  • Can hypothyroidism mimic bipolar disorder?
  • While research has looked into hypothyroidism and bipolar disorder, there is no significant association between the two conditions. However, some people with hypothyroidism experience moodiness or mood swings, but this is different from clinically diagnosed bipolar disorder, which is a serious mental health issue that should not be considered simple “moodiness.”
  • Can hypothyroidism make you feel crazy?
  • It depends on how you define “crazy.” Hypothyroidism is associated with psychiatric symptoms like depression, anxiety, and cognitive issues. For example, hypothyroidism may cause forgetfulness, slowed thinking, or moodiness. This could make you feel “out of it” or not yourself.
  • What mental illness is hypothyroidism often mistaken for?
  • Symptoms of depression, such as low mood and lack of interest in relationships or activities you usually enjoy, are common among people with hypothyroidism. Therefore, hypothyroidism is often mistaken for depression. A healthcare provider can distinguish between the two conditions by testing for thyroid hormone levels. If they come back abnormal, then thyroid issues are likely the underlying cause of depressive symptoms. However, if the tests come back and thyroid hormone levels are normal, then your healthcare provider may suggest further assessment, including tests for depression.

While research has looked into hypothyroidism and bipolar disorder, there is no significant association between the two conditions. However, some people with hypothyroidism experience moodiness or mood swings, but this is different from clinically diagnosed bipolar disorder, which is a serious mental health issue that should not be considered simple “moodiness.”

It depends on how you define “crazy.” Hypothyroidism is associated with psychiatric symptoms like depression, anxiety, and cognitive issues. For example, hypothyroidism may cause forgetfulness, slowed thinking, or moodiness. This could make you feel “out of it” or not yourself.

Symptoms of depression, such as low mood and lack of interest in relationships or activities you usually enjoy, are common among people with hypothyroidism. Therefore, hypothyroidism is often mistaken for depression. A healthcare provider can distinguish between the two conditions by testing for thyroid hormone levels. If they come back abnormal, then thyroid issues are likely the underlying cause of depressive symptoms. However, if the tests come back and thyroid hormone levels are normal, then your healthcare provider may suggest further assessment, including tests for depression.