In America, people enter the hospital involuntarily in a process known as civil commitment. On the other side of the pond, in Great Britain, it's known as being "sectioned."
My thanks to Mental Health @sectioned_ on Twitter who linked to this BBC radio program called "Shrink Wrapped" (not, not, not Shrink Rap) and a one-hour show on being Sectioned -- they interview a psychiatrist, a patient who has been sectioned roughly 10 times, and the police. Here's the Link if you'd like to listen. The issues sound to be the same on both sides of the Atlantic Ocean. If you'd like to listen, it may only be available for a few more days.