It’s easy to look at an author as successful as J.K. Rowling and assume that she has it made. However, it hasn’t always been that way for the author of the Harry Potter franchise.

One of the most sinister creatures in the series are the evil Lord Voldemort’s dementors, which are ghost-like entities that suck the souls out of humans. Rowling once discussed how these nightmare-inducing beings are actually representative of something equally as destructive: her depression. The creatures are described in the books as having the ability to “freeze your insides” and force their prisoners to be “trapped in their own heads,” something the author faced with her past mental health issues.

The story of the conception of Rowling’s novels is relatively well known. When she was a single mother, she started writing the famous series on her typewriter while waiting for a delayed train. But there’s a little more to the story than the popularized rags-to-riches timeline. When she was a struggling writer, Rowling was also being treated for clinical depression.

Following her initial venture into writing the stories, Rowling moved to Portugal where she got married and gave birth to her daughter Jessica, before separating from Jessica’s father, television journalist Jorge Arantes. The author said this was where she hit her lowest point.

Rowling has confirmed the dementors were in fact inspired by that low point. "That is exactly what they are," she said in a 2000 interview when asked if they are a symbol for depression. "It was entirely conscious. And entirely from my own experience. Depression is the most unpleasant thing I have ever experienced. It is that absence of being able to envisage that you will ever be cheerful again. The absence of hope.”

Rowling overcoming her struggles, and her use of them in her story, have proved to be an inspiration for fans everywhere.