As mentioned in the video below. This song was written for the sisters' grandfather, who suffered from schizophrenia. In general, the song describes watching someone you love, an older member of your family suffering from dementia and slowly slipping away as you watch and wonder when it will be your time.

The title is a common colloquial phrase, “mad as a hatter”, used to describe someone insane. The original phrase comes from hatters (i.e. people who made hats) who worked with mercury based substances for coating felt hats, and consequently were driven slowly insane by the constant exposure to the chemical.