The numbers are on the rise in people with a clinical diagnosis of major depressive disorder. In 2017, the National Institute of Mental Health found that 7.1% of the U.S. population had a diagnosis of major depression. Yet, these numbers only include people who seek out treatment and do not include people who experience mild to moderate cases of depression. Therefore, the amount of people struggling with any degree of depression is significant.
Treating depression is a complex process that often involves a combination of medication and therapy. When left untreated, major depression can have significant health consequences, including cardiovascular disease. Most doctors use antidepressants to help stabilize neurohormones that cause low feelings. Yet, antidepressants can disrupt other systems in the body, including thyroid function.
According to a 2018 study, there is a strong correlation between mental health and thyroid disease, particularly thyroid disease caused by autoimmune disorders such as Hashimoto's thyroiditis or Graves' disease.
The thyroid is the small (albeit mighty) butterfly-shaped gland at the base of your neck. It produces hormones that regulate your body's energy use, along with many other vital functions. When your thyroid hormone production drops (hypothyroidism), your body processes slow down and change, affecting virtually every system in your body.
People with thyroid disease can experience several mental health symptoms. Most notably, hypothyroid patients often have symptoms of depression and low mood.
Because depression and hypothyroidism share many similarities, misdiagnosis can be common. For example, people often conclude they have depression before exploring other causes like a thyroid condition. Sometimes, treating the thyroid is just the ticket for also managing low mood. However, this is not always the case in people who have clinical depression without thyroid involvement.
Research suggests that the hypothalamic-pituitary-thyroid axis is involved in the development of depression. As its name suggests, this axis depends on the hypothalamus, the pituitary gland, and the thyroid gland to regulate metabolism and respond to stress. The hypothalamus releases thyrotropin-releasing hormone (TRH). TRH stimulates the pituitary gland to produce thyroid-stimulating hormone (TSH). Then, TSH stimulates the thyroid to produce thyroid hormones thyroxine (T4) and triiodothyronine (T3). These thyroid hormones then create a feedback loop with the hypothalamus.
Like depression, hypothyroidism can manifest as a general sluggishness. For example, people with either (or both) conditions can experience fatigue, malaise, weight gain, disinterest, and lack of energy.
A blood test that measures thyroid function is necessary to confirm a diagnosis of hypothyroidism.
When people have depression unrelated to a thyroid condition, antidepressants can stabilize neurohormones and counter depressive feelings.
Recent research suggests that antidepressants alter thyroid hormone production. People who do not have a history of thyroid disease can develop hypothyroidism when taking antidepressants. Certain classes of antidepressants can interfere with thyroid hormone synthesis and iodine utilization.
The compounds in tricyclics can reduce biologically available iodine, an essential ingredient for making thyroid hormones. This class of antidepressants also binds with thyroperoxidase (an enzyme that helps make T4 and T3), reducing these hormones' availability for your organs. Thus, people can enter a hypothyroid state when taking this class of antidepressants.
Selective-serotonin reuptake inhibitors can cause hypothyroidism by inhibiting T4 and T3. Typically, hypothyroidism is where there is an increase in thyroid-stimulating hormone (TSH). However, people taking SSRIs do not always demonstrate changes in TSH levels. Alternatively, Non-SSRIs can cause significant thyroid hormone variations that can increase or decrease thyroid hormone levels. Thus, people taking non-SSRIs may be at risk for either hypothyroidism or hyperthyroidism.
Aside from watching your thyroid function, there are certain things you will want to keep your eye out for when taking antidepressants with a thyroid condition.
Most people with hypothyroidism and depression will see an improvement in their mood with thyroid hormone replacement medication. However, the amount of time it takes to see changes in your symptoms is based on the individual and can take weeks to months. Older adults who seek hypothyroidism treatment can expect it to take longer to see results, as thyroid medication is often titrated slowly in this population to avoid putting any strain on the heart.
Whether you have a thyroid condition or not, most people need to regularly monitor their thyroid function when taking antidepressants. However, if you have a thyroid condition, you will need to pay extra care to manage your thyroid.
Likely, your doctor will instruct you to keep a close eye on your symptoms. If you experience more thyroid symptoms after starting an antidepressant, it may indicate your medication is affecting your thyroid. You will also need regular blood tests when you titrate your antidepressant dose to verify that your thyroid function is not affected. Sometimes, your thyroid medication may need to be adjusted to counter the effects of your antidepressant.
There are other strategies for managing depressive symptoms aside from antidepressants. For example, your doctor may recommend lifestyle modifications and therapy to help support your mental health.
Blood sugar swings significantly impact our emotions. Eat more frequent meals to avoid the ups and downs, and consider increasing your healthy fats while limiting your carbohydrates.
Stimulants like caffeine or alcohol can affect our mood. For some, a genetic variation of the adenosine receptor (a protein) influences how we react to caffeine. Caffeine also forces the liver to make more glucose, which, as mentioned above, affects our blood sugar balance. Try a cup of hot lemon water or golden milk instead.
Research suggests that selenium intake may elevate mood and decrease anxiety. More selenium in your diet may help lower TPO antibodies and reduce stress, depression, and tiredness. Seafood, brazil nuts, and organ meats are the best food sources of selenium.
Stress and anxiety cause your cortisol levels to shoot up, which triggers the fight-or-flight response. Find a practice that helps you to calm your central nervous system each day. Try yoga, deep breathing, massage, or a warm bath.
Mental health symptoms may accompany hypothyroidism. Early detection and whole-body treatment of your thyroid condition are of the utmost importance. Work with a trustworthy thyroid doctor to understand your diagnosis and optimize your treatment.
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