One cause of depression can be a thyroid problem: more specifically, an underactive thyroid, also known as hypothyroidism. 

Yes, you read that right: hypothyroidism can lead to clinical depression.

The disease of hypothyroidism, when the thyroid is underactive, is commonly associated with weight gain or difficulty losing extra weight.

This component of low thyroid gets so much attention that the component of depression gets buried.

But clinical depression is one of numerous possible outcomes of a malfunctioning thyroid.

“When the body doesn’t create enough triiodothyronine (T3) or thyroxin (T4), it causes your thyroid stimulating hormone (TSH) to rise,” says Walter Gaman, MD, FABFM, board certified in family medicine and the author of several award-winning books including “Age to Perfection: How to Thrive to 100, Happy, Healthy, and Wise.”

“The body then experiences symptoms of depression, such as fatigue, loss of ambition, trouble concentrating and generalized feelings of sadness.

“Many doctors may immediately test your thyroid when you complain of these symptoms, while others will assume it is clinical depression without a primary source. This is why some patients do not respond to antidepressants.

“The flipside of this is that people with hypothyroidism may also develop clinical depression that has actually altered the brain chemistry.”

If you have symptoms of depression or know someone who is showing signs of depression, don’t blow off the possibility that an underactive thyroid can be the underlying cause.

A blood test will determine if the thyroid is working properly.

This doesn’t mean that most people with feelings of hopelessness and despair, lethargy, fatigue and loss of appetite have hypothyroidism.

But every person with depression should have a complete physical workup to see if thyroid hormone levels are normal.

Besides depression, classic symptoms of hypothyroidism include:

  • Often feeling cold even though the temperature is normal and everyone else in the room feels fine
  • Hair loss that doesn’t seem in alignment with male pattern baldness or aging
  • Hoarse voice
  • Fatigue and lethargy
  • Excessive sleepiness and wanting to sleep all the time
  • Moderate weight gain (though not all people with hypothyroidism will gain weight, especially if depression is killing their appetite
  • Constipation; and tingling in the hands and fingers.

A patient will not necessarily have every symptom listed here, and may only have a few at the time of diagnosis.

It’s interesting to note that sometimes, depression is the first clue that a person’s thyroid is not producing enough hormones.

“The thyroid medication alone may not be enough to reverse the symptoms, and an antidepressant may be necessary in the short run,” says Dr. Gaman.

Dr. Gaman is with Healthcare Associates of Texas and is with the Staying Young Radio Show 2.0 podcast.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.