England: If you're a danger to yourself or to other people there are various powers to detain you under section of the Mental Health Act.
If you're in public a police officer will use a section 136 - that's to take you to a place of safety and have you assessed by doctors.
If you're in a hospital nurses and doctors have powers to detain you for short times for you to be assessed.
If you're in your home your "nearest relative" (that person is defined in law) can ask the community mental health to consider assessing you. They must consider your request, but they don't have to do an assessment.
Or you can ask for an assessment. Or you could ask for a visit from your crisis[1] team, and they'll suggest an assessment.
In general it is much better to be an informal patient (someone who goes into hospital voluntarily) rather than someone detained under section.
In theory there should be a bunch of checks and measures. But, well, it's an imperfect world.
If you are ever detained you should ask for the Code of Practice (they have to have a copy available for patients. They have to help you read it if you're having trouble reading) and for an advocate. (They must make advocacy available for you.) make a record of everything that is said to you.
If you're in public a police officer will use a section 136 - that's to take you to a place of safety and have you assessed by doctors.
If you're in a hospital nurses and doctors have powers to detain you for short times for you to be assessed.
If you're in your home your "nearest relative" (that person is defined in law) can ask the community mental health to consider assessing you. They must consider your request, but they don't have to do an assessment.
Or you can ask for an assessment. Or you could ask for a visit from your crisis[1] team, and they'll suggest an assessment.
In general it is much better to be an informal patient (someone who goes into hospital voluntarily) rather than someone detained under section.
In theory there should be a bunch of checks and measures. But, well, it's an imperfect world.
If you are ever detained you should ask for the Code of Practice (they have to have a copy available for patients. They have to help you read it if you're having trouble reading) and for an advocate. (They must make advocacy available for you.) make a record of everything that is said to you.
(http://www.mentalhealthlaw.co.uk/Mental_Health_Act_1983_Code...)
(http://www.mind.org.uk/mental_health_a-z/8052_mental_health_...)