Although they're separate diseases, depression is sometimes a symptom of hypothyroidism. That’s when your thyroid gland doesn't make enough thyroid hormone. Medication can boost those levels, and that can improve or get rid of your symptoms, including depression.

The two conditions share so many signs that doctors sometimes overlook the possibility that someone who is depressed may also have low thyroid levels.

If you have hypothyroidism, you may have fatigue, sluggishness, and trouble concentrating. You may sleep too much, too. All of that may cause you to feel depressed.

At the same time, you could also have: