into a nuthouse

[kjc0123]

What is the meaning of "into a nuthouse" in the following sentences?

Turning now to Sophie, he gently took her hand, bowing his head slightly, breathing lightly on her fingers, and diverting his eyes. "M'lady."
Sophie glanced at Langdon, uncertain whether she'd stepped back in time or into a nuthouse.

[Sequin]

Nuthouse is a slang expression for an asylum - a place where people with mental problems would be held and treated

[THECORBYLOON]

• If a person is or appears to be mad we might say they are "nuts" and the place where they should be looked after is called a "nuthouse." A "nuthouse" is a place for those with a mental illness. Sophie is implying all the others are mad and she is the only sensible person there.