Produces
thyroxine.
Hyperthyroidism (or Thyrotoxicosis) (too much thyroxine/ over active thyroid ) most noticeable effect is 'bulgy eyes, ......Marty Feldman syndrome. Not sure how it's treated.
Hypothyroidism (too little) can mimic depression.
Main reason I post is because a family friend, many years ago committed suicide because of apparent depression in between the time her blood test was done & the results came back showing she had hypothyroidism. It is treated with thyroxine tablets. As an ex psych nurse, I reckon everyone who suffers depression should have a blood test to exclude hypothyroidism, especially as it's so easily treated.
My wife was recently told her thyroid levels were slightly low, possibly a menopause thing.
Cuppa