seccionar

While adding this entry into the dictionary, I thought of the verb 'to section' in British English meaning:

(from OALD) (BrE) to officially order a mentally ill person to go and receive treatment in a psychiatric hospital, using a law that can force them to stay there until they are successfully treated

I'd never thought about this meaning of 'section' being British English before. I guess in American English you would just say 'to commit sb (to a psychiatric hospital)' or 'to have sb committed' (both possible in British English too, of course).

What would we say in Catalan?

tancar? detenir?

One of the GDLC entries for tancar is

5 1 tr Posar dins un lloc tancat, privar de sortir d'un lloc, algú o alguna cosa. Tancar el bestiar a l'estable, al corral. Tancar un boig al manicomi. Tancar algú a la presó.

To "section" someone means to detain them under the Mental Health Act, for their own safety or for the safety of others.