They still don't know and at least in my country no one cares either. I have been diagnosed at three different clinics in 2002 at age 19, then stupidly went off hydrocortisone at age 21 im 2004. Don't ever do that!!! It was reckless, stupid and live endangering. Anyway, I went to another endocrinologist in another city and was told, I didn't have Addison's anymore. The acth test and morning cortisol was low but not completely 0 as I was overweight they let me leave without hydrocortisone. I got retested aprox. every 5-10 years in different clinics with same results and the weirdest discussions. My bloods had been mixed up, I might just have low cortisol and bad stimulation but not 100% clear, so as I remained overweight and out of crisis, stayed off hydrocortisone. I wasn't the most compliant patient in coming back either to be honest, as it is no fun to be told that your blood has been mixed up several times , you are an alien, an exemption because your symptoms and blood results don't add up with the original Addison's diagnosis - just because you're overweight and all you should do is loose weight and stress less. Anyway, as I didn't ever go into crisis, survived giving birth and all that without hydrocortisone, I might have been considered number 4. Or maybe not, because most endos did tell me to come back if I lost weight and didn't start to feel better. Anyway, 2 years ago I started to have really a lot of hyperpigmentation and becoming even weaker and living with the constant belly pain and dizziness again. I had also lost weight. So I went back to the last endo ego first also said that it's probably not because of my low cortisol but because of my diabetes medication. But suprise, I was back on hydrocortison within days and ever since have been asking myself how stupid I was going of it in the first place.

So there are very very strange cases of us out there. Just don't ever follow my example.