He has recently escaped from Dr Eustace’s private asylum for demented gentlemen.
Round the side of the Evening Telegraph he just caught a fleeting glimpse of her face round the side of the door with a kind of demented glassy grin showing that she was not exactly all there, viewing with evident amusement the group of gazers round skipper Murphy’s nautical chest and then there was no more of her.
There are no more uses of "demented" in the book.
Show samples from other sources
Stay away from her. She’s dangerous and demented.
Some demented killer has declared open season on people in nice cars.