How can i tell if a bipolar person needs hospitalization?

To protect life: Bipolar or not, a person who poses a threat to themselves or others is considered in need of hospitalization until stabilized and/or diagnosed as accurately as possible. If there is no violent or suicidal issues, it would not be the same sort of need, but it could be a recommended treatment choice to provide more intense focus and avoid interference from other aspects of daily life.

Bipolar: If a person is so manic or depressed that either medications aren't working or s/he's not taking them, the situation can become very dangerous, very quickly. Psychiatrists usually try to intervene before this point (& avoid hospitalization) -- but patients may not tell them when things are going south. Hospitalization is needed when the person isn't safe as an outpatient, or can't care for self.