By Dr. Mark Silvert & The SABI
It’s easy to assume that low mood or persistent anxiety is “just stress” or a chemical imbalance in the brain. But what if the cause of your emotional turmoil is hormonal—and hiding in plain sight? What if the root of your symptoms wasn’t in your brain—but in your neck?
The thyroid gland, a small butterfly-shaped organ located just below your Adam’s apple, has an outsized impact on your physical and emotional wellbeing. Its role in regulating metabolism, energy, temperature, and even brain function makes it one of the most influential—but often overlooked—players in our mental health.
For many people, thyroid dysfunction doesn’t start with a swollen neck or weight gain. It starts with mood changes: a creeping sadness that won’t lift, anxiety that spirals for no clear reason, or an emotional numbness that makes even joyful moments feel flat. These symptoms often lead to months, sometimes years, of misdiagnosis—being treated for depression or anxiety, when in fact, the issue lies in hormone levels that are too high or too low.
Thyroid imbalances—especially common in women—can mimic or amplify psychiatric conditions. And because the symptoms don’t always show up as textbook cases, many go undiagnosed or dismissed as “stress” or “burnout.” But understanding this gland-mind connection could be the missing piece to getting better.
In this article, we’ll explore how the thyroid works, how its dysfunction can manifest as mental health challenges, and why asking your GP to check your thyroid is a vital step—especially when low mood and anxiety appear out of the blue.
What Is the Thyroid—and Why Does It Matter So Much?
The thyroid is a small gland at the base of your neck, but don’t let its size fool you. It produces hormones—primarily T4 (thyroxine) and T3 (triiodothyronine)—that regulate how your body uses energy. These hormones affect nearly every system: your metabolism, heart rate, digestion, skin, menstrual cycle, and yes, your mood and cognition.
Think of thyroid hormones as the body's internal thermostat and metronome: keeping everything running smoothly, at the right pace. But when the gland becomes underactive (hypothyroidism) or overactive (hyperthyroidism), that rhythm falls out of sync—and your body and brain can feel like they’re spiraling.
The Physical Signs: More Than Just Tiredness
If your thyroid is underactive (hypothyroidism), you might notice:
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Constant fatigue, no matter how well you sleep
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Weight gain that doesn’t make sense
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Feeling cold when others are comfortable
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Slower digestion, dry skin, hair thinning
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Irregular periods
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Brain fog and memory lapses
If your thyroid is overactive (hyperthyroidism), you might experience:
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Unexplained weight loss despite eating more
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Feeling hot, sweaty, and jittery
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A racing heart or shakiness
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Trouble falling or staying asleep
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Mood swings, irritability, or nervous energy
But here’s the tricky part: for some people, the emotional symptoms come first—long before anything physical is obvious.
The Emotional Fallout: Depression and Anxiety That Doesn’t Respond to the Usual Fixes
Thyroid hormones affect the brain directly. They help regulate neurotransmitters like serotonin, dopamine, and norepinephrine—the same chemicals involved in mood, focus, and emotional regulation.
In hypothyroidism, your brain slows down. People often describe it as:
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A fog they can’t shake
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Feeling flat or emotionally numb
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Losing interest in things they used to love
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Being forgetful, distracted, or mentally “off”
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Feeling low, hopeless, or tearful without a clear reason
A study published in The Journal of Clinical Psychiatry found that up to 60% of people with hypothyroidism experience depression-like symptoms, even before diagnosis.
In hyperthyroidism, it’s the opposite: everything speeds up—too much. You might feel:
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Anxious, on edge, or panicky
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Restless and unable to sit still
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Easily overwhelmed
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Prone to racing thoughts or sudden mood swings
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A sense of internal chaos, even when things are calm
And if you’re postpartum? Watch this space. Postpartum thyroiditis, a temporary form of thyroid dysfunction after birth, is frequently mistaken for postpartum depression or anxiety—and often missed altogether.
Real Talk: It’s Not Just in Your Head
If you’ve been to the doctor with emotional symptoms, you might have walked away with a prescription for antidepressants or been told to try yoga. Both can help—but what if your thyroid is the missing link?
Thyroid disorders—especially autoimmune ones like Hashimoto’s or Graves’ disease—often creep in slowly. You might not have all the “classic” signs at once. What you have is a feeling that something’s off. You don’t feel like yourself, and it’s hard to explain why.
That gut feeling? It’s worth listening to.
Symptoms to Watch for (Especially If You’re Feeling Mentally Off)
If you're dealing with persistent mood changes, and any of these feel familiar, it's worth asking for a thyroid check:
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Exhaustion that sleep doesn’t fix
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Low mood, apathy, or sudden anxiety
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Brain fog, forgetfulness, or slowed thinking
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Weight changes without trying
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Feeling too cold or too hot all the time
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Menstrual cycle changes
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Hair thinning or dry skin
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A resting heart rate that’s too fast or too slow
What Your Doctor Can (and Should) Check
If you suspect thyroid involvement, ask your GP for a thyroid function test (TFT). A comprehensive panel includes:
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TSH (Thyroid-Stimulating Hormone) – the main screening test
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Free T4 and Free T3 – your actual circulating thyroid hormone levels
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Thyroid antibodies – especially Anti-TPO and Anti-TG, which can reveal autoimmune causes
Some people are told their thyroid is “normal” because only TSH was tested. But TSH alone doesn't always tell the whole story—especially if your body is struggling to convert T4 to the active form, T3.
If your symptoms don’t add up, ask for deeper testing.
Treatment: When the Gland Is Balanced, the Mind Often Follows
Hypothyroidism
Most commonly treated with levothyroxine, a synthetic version of T4. It’s taken daily and dosed according to blood levels and symptoms. Most people start to feel better within 4–6 weeks.
Hyperthyroidism
Treated with antithyroid medications (like methimazole), radioactive iodine therapy, or surgery in some cases. Beta-blockers can help with symptoms like palpitations and anxiety until hormone levels normalise.
The Emotional Recovery
When thyroid levels return to balance, many people report dramatic improvements in:
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Mood and emotional stability
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Energy and focus
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Sleep quality
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A sense of returning to themselves
However, some people benefit from temporary mental health support (such as therapy or medication) while the thyroid stabilises—especially if they’ve been struggling for a while.
Your Thyroid Deserves a Seat at the Table
Mental health is complex. Hormones, life stress, trauma, genetics, and environment all play a role. But if you’re facing unexplained depression or anxiety—and something doesn’t feel right—don’t overlook your thyroid.
It’s one of the most under-recognised causes of emotional distress. And it's one of the most treatable.
If you’ve been fighting to feel well and nothing seems to help, ask your GP for a full thyroid panel. It might just be the answer you’ve been waiting for.
References & Further Reading
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Bauer, M., et al. (2002). "Thyroid hormones, serotonin and mood: of synergy and significance in the adult brain." Molecular Psychiatry.
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Hage, M., & Azar, S. T. (2012). "The Link between Thyroid Function and Depression." Journal of Thyroid Research.
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Dantzer, R., et al. (2008). "From inflammation to sickness and depression: when the immune system subjugates the brain." Nature Reviews Neuroscience.
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British Thyroid Foundation. https://www.btf-thyroid.org/
About Dr. Mark Silvert
Dr Mark Silvert is a UK-trained Consultant General Adult Psychiatrist with over 20 years of experience across the NHS and private sector. He completed specialist training at Imperial College London and held Consultant roles at several major London hospitals. He also trained at Harvard Medical School and conducted research in Emergency Psychiatry at Massachusetts General Hospital. Dr Silvert treats a full range of adult mental health conditions and is regularly published in medical journals and media. He is recognised as London’s top-rated psychiatrist on the world’s largest independent doctor review platform.
HORMONAL & PROUD
Created as a brand to help women navigate the toughest moments in pregnancy, childbirth, postpartum — and practically every stage of life –– The SABI is changing the narrative around our hormones from one of taboo, embarrassment, and loneliness to awareness and even, pride. As more than a wellness brand, The SABI offers a carefully-crafted line of products to carry you through your hormonal journey, including rituals, supportive tools, and ancient herbal remedies that have been tested time and time again by women and now come backed by medicine. The SABI is a blend of science and nature conceived by women who have experienced the joys and deep struggles of bringing a child into the world, the pains of a heavy, difficult period, miscarriage, and difficulty conceiving.
We invite you to get to know your body and its cycles better –– to really understand what is going on inside. Learn to use your hormones to your advantage no matter your stage of life, and know that you can support and balance your hormone levels. We are here to help with the information, understanding and natural tools to support your body and the emotional process along with it.
DISCLAIMER
The SABI blog and articles are not meant to instruct or advise on medical or health conditions, but to inform. The information and opinions presented here do not substitute professional medical advice or consultations with healthcare professionals for your unique situation.
