In essence, the grounds are similar apart from the ‘appropriate treatment’ test. The person must suffer from, or appear to suffer from, a mental disorder (or the MHA wouldn’t be relevant), that disorder must cause some sort of risk for the person or other people (or there’s no need to intervene), the risk can’t be assessed or managed without the person being in hospital (we can’t detain someone in hospital if they don’t need to be in hospital) and the person isn’t agreeing to the admission (or they wouldn’t need detaining).