US laws about when someone can be detained in hospital against their will vary by state.
You're right that it tends to require immediate risk of harm to other people or to yourself. (And harm to yourself tends to mean risk of death. Self harm, even severe self harm, with no intent to die would usually not be something people are detained for. (Although I don't know much about the US systems.))
You're right that it tends to require immediate risk of harm to other people or to yourself. (And harm to yourself tends to mean risk of death. Self harm, even severe self harm, with no intent to die would usually not be something people are detained for. (Although I don't know much about the US systems.))