Short answer: Yes, the two are linked, but less strongly than researchers once assumed. A 2021 review of 25 studies in JAMA Psychiatry found that people with hypothyroidism had somewhat higher odds of clinical depression, and the link was clearest with overt hypothyroidism and in women. Most people with one don't have the other, per the American Thyroid Association's 2022 summary of that review. The symptoms overlap, and the ATA says a blood test is the only way to know for sure about hypothyroidism. Your mood is its own question.
If you've been told it's just stress
If you've sat in an appointment trying to explain that you feel flat, slow and foggy, and you're not sure whether it's your thyroid, your mood or both, this one is for you.
You're not imagining the overlap. The American Thyroid Association says it plainly in a 2022 patient summary: "Patients with hypothyroidism and those with depression can present with similar general symptoms." The same summary goes one step further: "A depressed mood is a common symptom of hypothyroidism."
And the National Institute of Mental Health (NIMH) says the same thing from the other side. Its depression guide, revised in 2024, names thyroid disorders among the conditions that "can cause the same symptoms as depression."
So two lists, written by two different institutions for two different conditions, end up describing a lot of the same days. You explained yourself fine. The overlap is what makes the question hard.
Where the two lists overlap
On the thyroid side, the lists are from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), MedlinePlus and the ATA. On the depression side, the list is from NIMH.
On both lists:
- Low mood. NIDDK and MedlinePlus list depression as a symptom of hypothyroidism, and the ATA's patient page says "Feel sad or down."
- Tiredness. NIDDK lists fatigue. NIMH lists "Fatigue, lack of energy, or feeling slowed down."
- Memory. The ATA's patient page lists "Forget things easily." NIMH lists "Difficulty concentrating, remembering, or making decisions."
- Weight. NIDDK and MedlinePlus list weight gain. NIMH lists "Changes in appetite or unplanned weight changes."
- Aches. NIDDK lists joint and muscle pain. NIMH lists aches or pains without a clear physical cause.
Only on the thyroid lists: trouble tolerating cold, dry skin, dry thinning hair, heavy or irregular periods and a slowed heart rate, per NIDDK and MedlinePlus.
Only on the NIMH list: feeling hopeless, guilty or worthless, losing interest in things you used to enjoy, and thoughts of death or suicide. None of these appear on the NIDDK, MedlinePlus or ATA hypothyroidism pages.
None of these rows settles anything on its own. NIDDK puts it directly: "A hypothyroidism diagnosis can't be based on symptoms alone because many of its symptoms are the same as those of other diseases."
How strong the link actually is
The question was already open before 2021. A 2013 review in the European Thyroid Journal by Dayan and Panicker concluded that "the relationship between thyroid function and depression remains poorly defined."
In 2021, Bode and colleagues published a review in JAMA Psychiatry that pooled 25 studies with 348,014 people. Overall, people with hypothyroidism had about 1.3 times the odds of clinical depression of people without it.
Split by type, the picture changes:
- Overt hypothyroidism, where thyroid hormone itself is low: about 1.77 times the odds, per the same 2021 review.
- Subclinical hypothyroidism, where only TSH is raised: about 1.13 times the odds in that review, a much smaller difference.
- Women: about 1.48 times the odds, per the same review. In men, it found no clear link.
The authors' own conclusion says it best. They wrote that the effect size was "considerably lower than previously assumed," and that the modest link was "possibly restricted to overt hypothyroidism and female individuals."
The ATA's summary of that review, published in April 2022, puts it in proportion: "most hypothyroid patients do not develop depression and the majority of people with depression do not have hypothyroidism."
So the 2021 review found a modest link, and found it in women but not in men. The honest answer is that research is still catching up.
Hashimoto's and depression: what the antibody studies found
If you have Hashimoto's, you may wonder whether the antibodies themselves are linked with low mood.
The same 2021 Bode review looked at thyroid antibodies on their own, the markers that point to Hashimoto's. The link with clinical depression "was inconclusive." The authors wrote that "Autoimmunity alone may not be the driving factor."
An earlier review, by Siegmann and colleagues in JAMA Psychiatry in 2018, reported a much stronger association between autoimmune thyroiditis and depression. Its studies varied widely, though, and the authors later published a letter with added data from a study they had left out.
Two reviews, two different answers, and neither settles it. The ATA's 2022 summary does say that hypothyroidism and depression "can also occur at the same time in the same person." If you want the background on what your antibody results are, we wrote it up in thyroid antibodies, explained.
What gets checked, and by whom
The two halves of this question get checked in different ways.
Your thyroid has a blood test. The ATA says doctors use two main blood tests, TSH and free T4, and that testing for T3 "is not often needed." NIDDK says health care professionals usually check TSH first. If you'd like to know what the different TSH and T4 patterns are called, start with high TSH, normal T4.
Your mood has its own check. The US Preventive Services Task Force recommends screening adults for depression. That recommendation, from June 2023, covers adults who haven't been diagnosed and don't show recognizable signs yet, and says people who screen positive are evaluated further. NIMH sets the bar for a depression diagnosis: symptoms "most of the day, nearly every day, for at least 2 weeks," with low mood or a loss of interest as one of them.
The two checks look at different things. One is a blood test for your thyroid. The other is a screen for depression.
The ATA's 2022 summary also notes that "symptoms of depression are not always resolved when hypothyroidism is corrected." So your mood can be its own topic at an appointment, whatever your thyroid levels show.
If you're having thoughts of suicide, don't wait for an appointment. Call or text 988, or chat at 988lifeline.org. The 988 Lifeline says it's available "24/7/365" and that conversations are free and confidential. In a life-threatening situation, call 911.
What to write down before your appointment
You don't need a theory about which one it is. You need a few weeks of dated, plain facts.
- How many days you felt low. A count, like eleven of the last fourteen days, says more than a general sense of it.
- Whether you lost interest in things, or just energy for them. NIMH lists "Loss of interest or pleasure in hobbies and activities" and "Fatigue, lack of energy, or feeling slowed down" as two separate signs.
- Sleep, as it happened. Too much, too little, waking early. NIMH's depression list includes sleep changes.
- The signs from the thyroid lists, if you have them. Trouble tolerating cold, constipation, dry skin, thinning hair, heavier or irregular periods.
- Every thyroid result you have, with its own lab's range and date. A number without its range says very little.
- What changed in your life and your medications, with dates. New prescriptions, a pregnancy, a birth. The USPSTF's 2023 depression screening recommendation includes pregnant and postpartum adults. We've also written about postpartum thyroiditis.
- Your own questions, in your words. Write them before you go, so they don't get lost in the room.
If perimenopause is also in the picture, we covered that overlap in is it perimenopause or is it your thyroid. And for the appointment itself, there's how to walk in with a real record.
Where Osmi fits
Osmi doesn't diagnose. What it does is keep your record, built from your own answers, ready for that conversation.
The daily check-in takes about a minute. You answer seven questions, things like energy and stress, or you talk to Rose, your thyroid mascot, who asks "How was today?" and lets you answer in your own words. Each lab result sits against the range your own lab printed. When two things line up, Osmi says they track with each other and stops there. Then it all goes onto one page you can share with your practitioner in a tap, with the questions you wrote yourself.
Start tonight with one answer about today. Two weeks from now, you'll have fourteen dated days to show.
Questions women ask about hypothyroidism and depression
Can hypothyroidism cause depression? The sources say the two are linked and that a depressed mood is a common symptom of hypothyroidism. A 2021 review of 25 studies in JAMA Psychiatry found people with hypothyroidism had about 1.3 times the odds of clinical depression, with the clearest link in overt hypothyroidism and in women. The same authors called the link modest. The ATA's 2022 summary adds that most people with hypothyroidism don't develop depression.
Does low mood with hypothyroidism feel different? The sources don't describe a separate version. The low mood, tiredness, trouble remembering and weight change on the thyroid lists are the same kinds of symptoms NIMH lists for depression. NIDDK says a hypothyroidism diagnosis can't rest on symptoms alone, and the ATA calls a blood test the only way to know for sure.
Is Hashimoto's linked to depression? The evidence is split. The 2021 JAMA Psychiatry review found the link between thyroid antibodies and depression "was inconclusive." An earlier 2018 review reported a stronger association for autoimmune thyroiditis, but its studies varied widely. The ATA's 2022 summary says hypothyroidism and depression can occur in the same person.
My thyroid levels are in range. Why do I still feel low? If your levels are back in range on treatment, the ATA's 2022 summary says depression symptoms "are not always resolved when hypothyroidism is corrected." If you aren't on treatment, NIMH says thyroid disorders can cause the same symptoms as depression, and that "A provider can rule out these possibilities by doing a physical exam, interview, and lab tests." Either way, your mood is its own topic, worth raising at your next appointment whatever your levels show.
Can an overactive thyroid affect mood too? The ATA lists "anxiety, nervousness, and irritability" and difficulty sleeping among hyperthyroidism symptoms. MedlinePlus says adults over 60 may have different symptoms than younger adults, and gives two examples: losing their appetite or withdrawing from other people. About those symptoms, it says "Sometimes this can be mistaken for depression or dementia."
Educational, not medical advice.
