Donoghue wanted to be clear about the real inspiration behind the story for Room. Many speculated that it was about Elizabeth Fritzl, who was held captive in an underground dungeon by her father for 24 years, was the root for her story. The author says that she “was triggered by it”. However, it was originally inspired by Felix Fritzl, one of Elizabeth’s 7 children. Felix was born in captivity and was only five years old when he was freed.

The thought of a 5 year old boy having the world he knew( in the cellar), completely crumble around him, and have new, loud, crazy world to live in and get to know, shattered Donoghue.
“That notion of the wide-eyed child emerging into the world like a Martian coming to Earth: it seized me.”
The feelings Donoghue experienced on hearing Felix’s story may have had something to do with the fact that her own son Finn was four at the time.

She had changed everything she could about Room’s story to separate it completely from the Fritzl case. Donoghue didn’t want to write a story about the Fritzls, so she set it in the America, giving Ma only one child to look after, having her kidnapper be a unknown, and putting their prison in a shed.

However, her book was often referred to as “the Fritzl Novel”.