There’s a link between thyroid hormone levels and your mental health.
Low levels of thyroid hormones (also called hypothyroidism) may slightly raise the risk of depression, mainly in women. Untreated hypothyroidism can also cause changes in mood, focus, or energy that often feel like depression. What’s more, hypothyroidism might show up just before or during menopause, a stage in life that itself can trigger a low mood.
“The symptoms of all these three conditions may significantly overlap,” says Prasanna Santhanam, MBBS, MD, an endocrinologist and associate professor of clinical medicine at Johns Hopkins University in Baltimore.
Here’s how thyroid medication, also called thyroid replacement therapy, can help some people living with severe or treatment-resistant depression.
When Can Thyroid Medicine Help Treat Depression?
If you’ve been diagnosed with depression, especially the treatment-resistant kind, you might get more relief by taking two medicines instead of one. Your doctor might suggest two kinds of antidepressants or an antidepressant plus another type of drug, such as thyroid medication.
Thyroid meds are lab-made versions of the main types of hormones that your thyroid gland makes: T3 (triiodothyronine) and T4 (thyroxine). T3 is the active form of the hormone that affects cells in your body. T4 is the inactive form that gets converted into T3 by your kidneys and liver.
The combo of an antidepressant plus thyroid medication is an option for treatment-resistant depression with or without hypothyroidism. If you have both conditions, your doctor might prescribe an antidepressant along with the lab-made version of T3, called liothyronine (Cytomel).
If you’re going through menopause and have depression as well as untreated hypothyroidism, treating each condition can help improve symptoms. “In general, the thyroid levels are measured after adequate [thyroid] hormone replacement, and if the levels are optimal, then attention is given to depression and menopause management,” Santhanam says.
If you have depression without hypothyroidism, your doctor might still recommend an antidepressant plus thyroid medication, although “I don’t see it done as much now,” says Paul Kim, MD, PhD, an assistant professor of psychiatry and behavioral sciences, and medical director of the Johns Hopkins Esketamine Clinic in Baltimore.
When Can Thyroid Medicine Help Treat Depression-Like Symptoms?
Hypothyroidism can cause symptoms that look like those of depression.
“Maybe your main initial presenting symptom of hypothyroidism is low mood. And you end up seeing a psychiatrist because you say, ‘Well, I have a low mood. I'm feeling tired all the time. My concentration is off.’ And maybe your motivation or drive is also decreased,” Kim says. The psychiatrist might then say, “Yeah, this sounds like depression,” and start you on antidepressants. And then you realize it’s not working because you’re not really treating the underlying cause of those symptoms, which is hypothyroidism.”
Once you get diagnosed with hypothyroidism, you can get relief from the range of symptoms it causes by taking lab-made T4, a treatment called levothyroxine (Levo-T, Synthroid). “Your mood gets better, and all those quote-unquote depressive-like symptoms go away,” Kim says.
How Often Might You Need Follow-Up Tests?
Your doctor will likely recommend tests to check on how well your treatments are working. When one of Santhanam’s patients gets treatment for depression and hypothyroidism, he does blood tests to check their thyroid-stimulating hormone (TSH) and thyroid hormone levels every six to eight weeks until the TSH and thyroid hormone levels are at goal based on the patient’s individual circumstances. TSH is a hormone from your pituitary gland that causes your thyroid to release thyroid hormones. Psychiatrists, meanwhile, may suggest follow-up checkups for treatment-resistant depression every one to four weeks at first.
If you take certain depression medications, your health care team may also be on the lookout for possible effects on your thyroid gland or the hormones it makes. Take lithium, for example. It’s a drug that treats certain mental health conditions and is sometimes prescribed along with an antidepressant for treatment-resistant depression. Lithium use is linked with a higher risk of hypothyroidism over time.
Selective serotonin reuptake inhibitors (SSRIs), the most commonly prescribed type of antidepressant, can sometimes lower the level of free T4 hormone in your blood marginally without too many changes in TSH, but this doesn’t seem to have a clinical impact, Santhanam says.
Can Antidepressants and Thyroid Medication Affect Each Other?
Kim says the chance of that happening is low: “As far as I know, the interaction is very minimal, so it’s pretty safe to be on both drugs,” like SSRIs and thyroid meds.
What Lifestyle Changes Might Help?
You can follow some healthy habits that are generally good for your mental health and thyroid health:
Eat a balanced diet. For instance, you could try the heart-healthy Mediterranean diet, Santhanam says. It focuses on nutritious whole foods such as fruits and vegetables, whole grains, nuts and seeds, and olive oil.
Use caution with supplements. Always talk to your doctor before you try a new supplement. It could affect your medications in ways you didn’t expect. For instance, calcium and iron supplements may affect how well your body absorbs the thyroid medication levothyroxine, especially if you take them together, Santhanam says.
Get regular physical activity. Moving more can be a natural mood-booster. If you’re not active now, ask your doctor to help you get started. Try to slowly work up to getting either 150 minutes of moderate-intensity aerobic activity a week or 75 minutes per week of vigorous aerobic activity a week, or a combination of both. Also aim to do some type of strength-training, such as weightlifting, two days a week.
Get enough sleep. Adults need about seven hours of shut-eye a night. Going to bed and waking up at the same times each day can be helpful. Let your doctor know if you’re regularly having a hard time falling or staying asleep.
Take charge of stress. You may know that too much stress can deepen depression. It might also worsen symptoms of hypothyroidism. To help manage stress, get regular exercise and quality sleep, make time for hobbies that relax you, and try techniques such as meditation, deep breathing, or yoga.
