Hi All, My doctor suspects I have diabetes insipidus. I have had fibro for over 4 years. The last 8 months I have had v bad fatigue and been very stiff when waking in the middle of the night which I didn't used to get. The last 2/3 months I have also had excessive urination and thirst, dry mouth and skin, urinate over 3 litres per 12hrs. Theres a condition called diabetes insipidus which is to do with the hypothalamus not producing a anti-diuretic hormone to do with the pituitary gland. I am seeing my doctor tomorrow hopefully for more tests, it's something I wanted to share with others in case people have extreme thirst and excessive urination. It's not diabetes mellitus for me as I don't have glucose in my urine. THe symptoms of diabetes insipidus if it has continued for a while are also fatigue, muscle pain and stiffness. I suspect there may be a few of us with this added disorder due to our hypothalmus function and dehydration. Any info would be appreciated.