And the answer: Susanna Kaysen.
Adapted for film by James Mangold and Lisa Loomer in 1999, Susanna Kaysen penned the semi-autobiographical memoir in 1993. Much like her book's main character, Kaysen was diagnosed with borderline personality disorder at 18 years old.
In the winter of 1999, amidst a wave of other memorable (or soon-to-be-memorable) new releases such as 10 Things I Hate About You and American Pie, came one film that prompted unique conversations on the treatment of mental health: Girl, Interrupted. Growing out of Kaysen’s experience in a mental institution in 1967, the story follows a protagonist of the same name played by Winona Ryder, as she is brought to a mental institution and forced to grapple with her unfortunate reality.
Although actress Ryder stars in the film, she was so passionate for its message that after reading the novel at 21 years old, she immediately sought the rights to create a film adaptation. The connection meant something significant to Ryder, who just a year prior had struggled with her own mental health and checked herself into a mental institution following a breakup with Johnny Depp. Upon seeking the rights to the film, she fortunately found that producer Douglas Wick already had them, and brought Ryder into the groundwork of Girl, Interrupted as a creative partner.
Ultimately, Ryder’s creative vision alongside the authenticity of the plot drew audiences from all walks of life. As Ryder explained in 1999:
"I hope the teenagers who feel alone out there will see this movie and say, 'Thank God.’ Because movies like this aren't really offered, and I would like to offer it. If I had seen this movie at 19, I would have taken a lot of comfort in it… Life is just weird. Life is a mess. This world is a mess, and anyone who understands this world I would worry about… We're normal to feel crazy, in a way."
Learn more about the making and background of Girl, Interrupted here.