What is Overactive Bladder?

Overactive bladder causes the frequent urge to urinate. Many people with overactive bladder will find that they have to urinate frequently during the day, even if their bladder is not full. Many people with overactive bladder will also wake up in the middle of the night, feeling the need to urinate. Overactive bladder is caused by involuntary contractions of the bladder that signal to the brain that there is an urgent need to urinate.