I was diagnosed with hypothyroidism about six months ago after over three years of symptoms: weight gain, constant tiredness, lack of focus and concentration. Being not totally ignorant of human diseases, I wondered if my thyroid had gone south on me, but the first general practitioner I visited -- the type who pops in for two minutes, long enough to say "Hihowyadoing?" and write a prescription -- had his nurse take a blood sample and later cheerfully told me that my test results were perfectly normal and that I was likely "just depressed" and did I want to go on Zoloft?

I spent most of my early 20s wrestling with depression. I know damn well what sinking into that pit feels like, and knew it wasn't the problem. So I declined, and went looking for another doctor. The doctor I found -- our current doctor -- spent a whole hour talking with me about my symptoms and taking notes. She believed me when I told her I wasn't "just" depressed, and took more blood.

This time, I got my test results in the mail with a handwritten note from my doctor that I did indeed have a sluggish thyroid.

She subsequently put me on Synthroid. We haven't worked out a truly effective dosage yet -- after the first couple of weeks of "Holy shit, I feel alive again!" I've felt less good (though better than before), but in regard to hormone levels, the initial dose of 25 micrograms wasn't doing much. She put me on 50, and that doesn't seem much different so far -- so I get to keep going back for more bloodwork until my hormone levels look normal.

The thing about thyroid testing is that it's fiddly, and the results have to be seen by a knowledgeable eye. A nurse I know has speculated that the first doctor might not have even bothered getting my sample tested because he'd already decided I was depressed. Another possibility is that I spent several years being "sub-clinical": I was having symptoms, my levels were low, but still "normal" according to some diagnostics.

So, the take-home message is this: if you suspect you might have hypothyroidism, be persistent. See a real endocrinologist if you can rather than a general practitioner. Get tested in another six months (or a year, if that's what you can afford -- right now the bloodwork runs a little over $100 and as with anything medical is more likely to rise rather than become more affordable). Hormone levels change.

If left untreated, hypothyroidism can ultimately cause some fairly serious heart problems.

Everyone is affected somewhat differently, but the common signs and symptoms of hypothyroidism include:

Doctors insist that the decrease in metabolism isn't enough to account for much weight gain in most people. However, with hypothyroidism I feel you're likely to gain weight simply because you're too damn tired to exercise and you crave a lot of carbohydrates to try to give yourself some cheap energy. Before I was properly diagnosed, I mostly felt like lying down someplace.

Physically, I constantly felt the way I do after a long day, and mentally felt like I'd just woken up. I am not a morning person; I feel pretty groggy for the first half-hour or so. I was like that all blessed day: groggy and bone-tired.

There are certainly many far worse diseases, but speaking as a geek, this one nontrivially hurt my life because it killed my memory and concentration. I gradually lost the ability to read for more than 20 minutes at a time, and I had trouble retaining what I'd just read. Study for my A+ certification? Go back to college? Even just get through all the stories for a writers' workshop meeting? I just couldn't do it.

It was as if this disease aged me 15 years and cost me 30 IQ points.

Hypothyroidism is more common in women, and in people with prematurely gray hair.

If you're a woman, and the hypothyroidism didn't affect your menstrual cycle, be aware that your thyroid medication probably will, at least initially. More to the point, it might make your periods late, possibly weeks late.

If you go on Synthroid, it's best to take your pill first thing in the morning before you've eaten, and you'll have to wait an hour until you have breakfast. Calcium supplements, soy, and walnuts don't play well with Synthroid, so avoid soy shakes and Tums tablets until much later in the day.

Exercise does play well with Synthroid, though, and if you get active you'll feel much better than if you take your pills but stay sedentary.

They don't really know yet what causes most garden-variety cases of hypothyroidism like mine. Yes, your thyroid stops working -- but why? My husband also has hypothyroidism, and was being treated for it long before I started showing symptoms. So, I suspect a virus, probably one that some people are more vulnerable to genetically. It'll probably be a while before anyone comes up with any research results to prove me right or wrong.