Your thyroid is a butterfly-shaped gland at the front of your throat that secretes hormones. These hormones regulate your metabolism, energy levels, and other vital functions in your body.

More than 12 percent of Americans will develop a thyroid condition in their lifetime. But as many as 60 percent of those who have a thyroid condition aren’t aware of it.

Thyroid disease has some symptoms in common with certain mental health conditions. This is especially true for depression and anxiety. Sometimes thyroid conditions are misdiagnosed as these mental health conditions. This can leave you with symptoms that may improve but a disease that still needs to be treated.

Let’s take a closer look at the links among thyroid conditions, depression, and anxiety.

Researchers have known for a long time that people who have thyroid conditions are more likely to experience depression and vice versa. But with the rising diagnosis rates of anxiety and depression, there’s an urgency to revisit the issue.

Hyperthyroidism is a condition characterized by an overactive thyroid. A review of the literature estimates that up to 60 percent of people who have hyperthyroidism also have clinical anxiety. Depression occurs in up to 69 percent of people diagnosed with hyperthyroidism.

Hyperthyroidism is connected in particular to mood disorders and bipolar depression. But the research is conflicting as to how strong this connection is. One 2007 study revealed that thyroiditis is likely connected to having a genetic predisposition of bipolar disorder.

On top of that, lithium can aggravate or trigger hyperthyroidism. It’s a prevalent treatment for bipolar depression.

Hypothyroidism is a condition characterized by a “sluggish” or underactive thyroid. It’s linked specifically to depression in some literature. The deficiency of thyroid hormones in your central nervous system can cause fatigue, weight gain, and a lack of energy. These are all symptoms of clinical depression.

If you have hyperthyroidism, your symptoms may have a lot in common with clinical anxiety and bipolar depression. These symptoms include:

  • insomnia
  • anxiety
  • elevated heart rate
  • high blood pressure
  • mood swings
  • irritability

Hypothyroidism symptoms, on the other hand, have a lot in common with clinical depression and what doctors call “cognitive dysfunction.” This is memory loss and difficulty organizing your thoughts. These symptoms include:

  • bloating
  • weight gain
  • memory loss
  • difficulty processing information
  • fatigue

The overlap in thyroid conditions and mood disorders can result in a misdiagnosis. And if you’ve been diagnosed with a mental health condition but have an underlying thyroid condition, too, your doctors might miss it.

Sometimes a blood panel that’s testing your thyroid-stimulating hormone (TSH) can miss a thyroid condition. The T3 and T4 hormone levels are specific indicators that can reveal a thyroid condition that other blood tests overlook.

Hormone supplementation for a thyroid condition can be related to depression. Thyroid hormone replacement aims to bring your body back to its normal hormone levels if you have hypothyroidism. But this kind of treatment can interfere with medications for depression.

Medication for depression can be what’s decreasing or impacting your thyroid function. There’s a long list of medications that can have this effect. Lithium, a popular treatment for bipolar depression, can trigger symptoms of hyperthyroidism.

If you’re having symptoms of depression, you may be wondering if there is a connection to your thyroid. Even if your TSH levels have tested as normal, it’s possible that there’s more to the story of how your thyroid is functioning.

You can bring up the possibility of a thyroid condition to your general practitioner, family doctor, or a mental health professional. Ask specifically for the T3 and T4 hormone level screening to see if those levels are where they should be.

What you should never do is discontinue medication for a mental health condition without speaking to a physician.

If you’re looking for alternative treatments and new ways to address your depression, make a plan with your doctor to gradually switch dosages of your medication or incorporate supplements into your routine.