Diabetes insipidus (DI) causes frequent urination. You become extremely thirsty, so you drink. Then you urinate. This cycle can keep you from sleeping or even make you wet the bed. Your body produces lots of urine that is almost all water.
DI is different from diabetes mellitus (DM), which involves insulin problems and high blood sugar. The symptoms can be similar. However, DI is related to how your kidneys handle fluids. It's much less common than DM. Urine and blood tests can show which one you have.
Usually, DI is caused by a problem with your pituitary gland or your kidneys. Treatment depends on the cause of the problem. Medicines can often help.
NIH: National Institute of Diabetes and Digestive and Kidney Diseases