Healthy Hormones

Hypothyroidism and Depression – Is There a Connection?

Is there a connection between hypothyroidism and depression?

Will taking thyroid medication reduce or even eliminate depression symptoms?

Do you still have depression even though you are on thyroid medication?

In this article, I will discuss the connection between hypothyroidism and depression, how thyroid medications can often help both conditions, and other causes of depression that you should consider...


The Connection Between Hypothyroidism and Depression

It is a well known fact in medicine that hypothyroidism is often associated with symptoms of depression. You will commonly find it listed as a symptom of hypothyroidism.  Click here for an example.

Doctors are even taught to check thyroid lab tests in any patient that presents with new symptoms of depression.

But how exactly are they connected?  We aren't completely sure.

However, we do know these connections:

  • Hypothyroidism and depression share similar symptoms.
  • Depression symptoms resolve in some people that are treated for hypothyroidism.
  • Thyroid hormone increases serotonin levels in the brain.
  • Thyroid Releasing Hormone (TRH) is sensitive to serotonin.  Low serotonin levels may stimulate TRH production, while high serotonin levels may lead to lower TRH production.

Basically, depression symptoms can sometimes (but not always) be due to hypothyroidism.  If you treat the hypothyroidism, the depression symptoms will reduce or even resolve.

Let's talk about depression a bit more...

What Is Depression?

So what is depression anyway?  Most of us have no problem explaining the common symptoms that we call depression.

When several people share a similar group of symptoms, medical organizations like to give it a name. This is to make things more simple, but it also makes it easier to bill insurance.

The Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) lists the following criteria required to diagnose depression:

  • Five (or more) of the following symptoms have been present during the same 2-week period and represent a change from previous functioning; at least one of the symptoms is either (1) depressed mood or (2) loss of interest or pleasure.

    Note: Do not include symptoms that are clearly attributable to another medical condition.

    1. Depressed mood most of the day, nearly every day, as indicated by either subjective report (e.g., feels sad, empty, hopeless) or observation made by others (e.g., appears tearful). (Note: In children and adolescents, can be irritable mood.)

    2. Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (as indicated by either subjective account or observation.)

    3. Significant weight loss when not dieting or weight gain (e.g., a change of more than 5% of body weight in a month), or decrease or increase in appetite nearly every day. (Note: In children, consider failure to make expected weight gain.)

    4. Insomnia or hypersomnia nearly every day.

    5. Psychomotor agitation or retardation nearly every day (observable by others, not merely subjective feelings of restlessness or being slowed down).

    6. Fatigue or loss of energy nearly every day.

    7. Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional) nearly every day (not merely self-reproach or guilt about being sick).

    8. Diminished ability to think or concentrate, or indecisiveness, nearly every day (either by subjective account or as observed by others).

    9. Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide.

  • What this fails to take into account is what condition or conditions caused the symptoms in the first place!

    If you are fatigued, moody, and are gaining weight since you hit menopause, should you be treated the same way as someone that just went through a divorce, or someone that is anemic, or someone who has an autoimmune disease?

    Of course not!

    Don't think of depression as a diagnosis.  Instead, think of depression as a group of symptoms that may be caused by many different conditions.

    In other words, it is a side effect of one or more other problems.  In order to properly treat the depression, the root cause must be identified and addressed.  This is the foundational principle of functional medicine.

    Possible Causes of Depression:

    1.  Hormone Imbalances

    An imbalance in one or more hormones commonly results in symptoms of depression.

    An abnormality in these hormones should be one of the first things that you consider and test for when you are investigating the cause of your depression.

    Examples of hormone imbalances includes menopause, low testosterone, and hypothyroidism.

    2.  Nutrient Deficiencies

    Nutrient deficiencies commonly cause anemia and other conditions that result in depression symptoms.

    These include B12, folic acid, and iron.

    If you don't test for them you will never know if you are deficient or not!

    3.  Gut Dysfunction

    Gut dysfunction can lead to the nutrient deficiencies listed above, it can result in a decrease in neurotransmitter production such as serotonin, and it is a primary reason why autoimmune disorders develop.

    Most diseases in the body is worsened or even starts with gut dysfunction.  In fact, when I have a difficult patient and I'm not sure what to do, I start with working on their gut.

    Gut issues include lack of stomach acid, SIBO or SIFO, and dysbiosis.

    4.  Inflammatory States

    Inflammation causes a decrease in energy production in the mitochondria of the cells.  This results in fatigue, insomnia, chronic pain, and other symptoms of depression.

    Examples include insulin resistance, leptin resistance, autoimmunity, and acute and chronic infections.

    Most of these can be detected with proper lab testing.

    5.  Insomnia

    Lack of sleep causes mood swings, fatigue, poor concentration, and other symptoms of depression.

    6.  Alcohol Use

    Alcohol abuse has been shown to be associated with depression in several studies.

    7.  Stress

    Stress (particularly chronic stress) has been closely associated with depression.

    8.  Spiritual/Religious Issues

    Studies have shown that pursuing religion and spiritual beliefs can help reduce depression symptoms.  Guilt and conviction of not following or pursuing your personal religious beliefs could be a major source of stress that will need to be addressed.

    IT IS IMPORTANT TO REALIZE THAT it is possible and even probable that your depression is multifactorial - meaning it could be caused by several of the reasons listed above.

    Treating only one of the causes may not significantly reduce your symptoms.  It will be necessary to address ALL of the causes to get the most benefit.

    Hashimoto's and Depression

    Since up to 90% of hypothyroidism is caused by Hashimoto's Thyroiditis, it deserves discussion as well.

    As you know, Hashimoto's is an autoimmune disorder that if left untreated will slowly and gradually destroy the thyroid gland, resulting in hypothyroidism.

    One of the things that makes Hashimoto's even more difficult than hypothyroidism is the fact that the TSH will often be in the "normal" range even though the patient may be having significant symptoms such as depression, constipation, fatigue, etc.

    That is important because if the TSH is normal, very few doctors will give those patients thyroid medication, even if they have are having symptoms.  As we will discuss later in this article, thyroid medication can often greatly reduce depression symptoms.

    Studies show that patients with Hashimoto's are at increased risk of developing both depression and anxiety, even when their TSH is normal.

    In fact, it appears that thyroid antibodies themselves can actually cause depression symptoms.

    It is therefore crucial to get a complete thyroid panel, including free T4, free T3, TPO antibody, and thyroglobulin antibody levels.  That will give you an indication of whether you are deficient in thyroid hormone at the cellular level and if you have autoimmune thyroid disease.

    If someone is having depression symptoms and they have a normal TSH but a low free T3, starting a trial of thyroid hormone medication may be warranted.

    They may also benefit from other Hashimoto's therapies that help reduce antibody levels.  These can include selenium and zinc supplementation, vitamin D supplementation, LDN therapy, and others.  I discuss many of these in other blog articles on my website.

    Click here to read more about treatments for Hashimoto's.

    Treatment of Depression with Thyroid Medication

    Studies have shown that thyroid medication can be very effective in treating depression and depression symptoms.

    It can reduce depression symptoms when added to an SSRI (the standard conventional treatment for depression) as shown in this study.

    Giving T3 medication has also been shown to be effective at treating depression even when patients are resistant to standard SSRI treatment.

    There are also studies that show using T3 by itself is effective at reducing depression symptoms.

    Of note, T3 has also been shown to be effective in treating mood disorders such as bipolar disorder, even when patients have failed multiple mood stabilizing medications.

    So why does thyroid hormone (particularly T3) help with depression?

    These studies show that there is probably a connection between mood and thyroid function.

    There may even be a subset of depressed patients that actually have hypothyroidism that has not been identified.

    There is also the possibility that some patients may have a genetic defect in one of the deiodinase enzymes that converts T4 to T3.  This may result in a decreased level of T3 circulating in the brain.

    I believe that it is good medicine to have a complete thyroid panel drawn on all patients that have symptoms of depression.  

    If you have failed multiple depression therapies and medications, it would even be reasonable to try a trial of thyroid medication, especially if your free T3 level is not optimal.

    The best thyroid medication to use is Cytomel or liothyronine, which is a T3 only medication.  This is the strongest thyroid medication available and does not require conversion by a deiodinase to work.

    This can be done safely if these guidelines are followed, which is further explained in this article:

    • Check TSH, free T3, and free T4 prior to starting treatment
    • Start with liothyronine 25mcg daily and titrate slowly over weeks depending on tolerance to the medication.  Most patients will need 50-150mcg daily
    • Recheck thyroid labs at least every 3-6 months, or more often if needed
    • The goal for TSH should be in the lower limits of the reference range (or even lower at times depending on the free T3 level)
    • The goal for free T3 should be in the upper limits of the reference range
    • If you are menopausal, bone density should be monitored regularly

    T3 medications can sometimes cause side effects such as jitteriness, palpitations, excessive sweating, headache, and other symptoms.  Make sure you communicate any of these with your doctor if you are taking T3 medication.

    Some people simply cannot tolerate liothyronine due to side effects.  In those situations, a compounding pharmacy can make sustained-release T3 (SR-T3) which is typically much better tolerated.

    7 Steps to Consider if You Have Depression

    If you are suffering from depression, I would recommend that you follow the 7 steps below to help reduce or eliminate your symptoms:

    1.  Get a Complete Thyroid Panel

    Just checking a TSH level is woefully inadequate to truly evaluate your thyroid function.  Instead, I STRONGLY recommend that you ask your doctor to check all of the following tests:

    If either antibody test is >35, then a diagnosis if Hashimoto's Thyroiditis can be made.

    If the free T3 level is < 3.5, that is an indication of hypothyroidism regardless of the TSH level, especially if you are having several symptoms of hypothyroidism.

    2.  Consider adding T3 medication to your current regimen

    Many people have issues with T4 to T3 conversion due to chronic inflammation and gut issues.  Adding T3 to your other thyroid medication bypasses the need for the conversion step which will allow more active thyroid to reach the cells of the body, including the brain.

    As little as 5-10mcg of liothyronine can be helpful.

    3.  Reduce your thyroid antibodies if you have Hashimoto's

    Reducing thyroid antibodies will help in numerous ways.  This includes reducing systemic inflammation which improves thyroid conversion plus helps you feel better in general.  It also reduces depression symptoms directly.  Finally, it typically improves hypothyroidism which will help reduce symptoms.

    4.  Identify and treat and nutrient deficiencies

    These include vitamin B12, folate, and iron.  There are lab tests that test for these directly.  Treatment consists of supplements and improving gut health.

    5.  Get good sleep

    It is almost impossible to maintain good overall health if you are getting less than 7-8 hours of good sleep per night.

    Here is a fascinating interview of Matthew Walker, a neuroscientist who is considered one of the premiere sleep experts in the world if you want to learn more (warning- there is cursing by the host in the interview).

    Improving your sleep may actually be the single most potent tool that you can do to combat your depression.

    6.  Manage your stress

    This is always an easy thing to say, but a hard thing to do.

    Reducing your stress may need to include changing jobs, ending unhealthy relationships, and placing healthy boundaries in your life.

    I would also recommend adding meditation and/or yoga to your daily routine.  

    7.  Address any spiritual needs

    Depending on your particular situation, this can include speaking to your pastor, priest, or spiritual advisor, and re-committing yourself to pursue a deeper meaning in your life.

    Important Note:  You may still need the use of an anti-depressant (at least for awhile), but finding the root causes of your depression and dealing with them directly will greatly improve your success in reducing or eliminating your depression symptoms.


    Many patients that have been diagnosed with depression also have thyroid issues, including hypothyroidism and Hashimoto's.

    In many cases, adding T3 thyroid medication can reduce depression symptoms, even when their TSH is normal.

    If you have depression and hypothyroidism and are taking a T4 only thyroid medication, you may want to talk to your doctor about adding T3 or changing your thyroid medication to one that contains T3.

    It is important to get a complete thyroid panel to accurately assess your T3 levels and to check for the presence of Hashimoto's.

    As with most conditions, finding the root causes of your depression will allow you to directly address the issues that apply to you.

    Now it's your turn...

    Do you have a thyroid issue?  Do you also have depression?

    Have you tried taking T3 medication to treat your depression?

    What has worked for you?  What hasn't worked?

    Leave your questions and comments below.

    About the Author Dr. Jeff Whelchel

    Dr. Whelchel is a family physician who specializes in functional medicine, especially hormone optimization. He has over 20 years experience in private practice managing patients with various medical issues. His passion is helping patients reach their full potential of wellness and quality of life. He grew up in the Texas Panhandle where he currently lives. He is married and has 3 awesome children.

    Leave a Comment:

    Donna says April 20, 2022

    Hello Dr.
    I had a sluggish thyroid, with tsh 3; t4 and t3 in the normal range and I was advised by NP that i would feel better on thyrod meds. Well, I took Synthroid 50m and didn’t feel any better so my dr. put me on NP thyroid and I starting losing my hair,etc. We then put me on on another T4 and added T3 5m slowly and i had major hypothyroid systems, fatigue, irritability, weight gain, puffy face, massive hair loss, etc Labs during this time raised my tsh levels. Went back to Synthroid for 3months and no decrease in TSH so, went went to compounded Nature throid 32mg, i felt much better. After 2 months didn’t as good and my labs decreased TSH from 4 to 3, yet it decrease my T4 and T3 to the bottom of the normal range. Dr thought maybe my serotonin was interfering with the pitutary gland. In the meantime i went to a compounding pharmacy and they recommended I take the estended release T3, and I informed them of the massive side affects. I shared the chronic stress i was under for 4 years and she gave me Adrenal Desicated. I felt great for 2 weeks and now back to feeling sluggish and gained 30 pounds during this treatment. Per an endocrinologist I should have not be treated for my thyroid, and if i am going to continue treatment i need to get closer to something like 1-2 TSH, which I was not able to accomplish the past year on the T4 and NDT. My iodine is on the lowest range reference and all other labs, nutrients look good. To conclude, i felt worse treating my thyroid and was hoping maybe I could get off meds, however I fear that my natural thyroid will not kick back in, and will go hypo and lose even more hair, weight etc. The other idea is to change the adrenal med and see if it helps my tsh production, or increase Nature throid and add SR T3. I would love your thoughts. Donna

      Dr. Jeff Whelchel says May 10, 2022

      Hi Donna. Lots going on with you. Based on your history, I wonder if you have undiagnosed Hashimoto’s. Make sure they check a complete thyroid panel – TSH, free T4, free T3, reverse T3, TPO antibodies, and thyroglobulin antibodies. I would also consider getting an adrenal workup. You should also get your iron and ferritin levels checked. I don’t have a definitive answer for you, but don’t give up trying. Something is going on that needs to be addressed. Best of luck.

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