Intriguing & Mysterious:
* The Whispering Walls
* Echoes in the Asylum
* The Girl in Ward 13
* The Sanitarium's Shadow
* Silent Screams
* The Unseen Hand
* The Truth Behind the Bars
* The Patient's Diary
Suspenseful & Dramatic:
* Trapped in the Asylum
* Innocent in the Madhouse
* The Ghost of Elmwood Manor
* Whispers in the Dark
* The Girl Who Knew Too Much
* In My Mind, I Am Free
Emphasizing the Girl's Strength:
* Unbreakable
* The Untamed Heart
* Rise from the Ashes
* The Girl Who Found Her Voice
* Breaking the Chains
More Specific & Emotional:
* The Last Dance of the Innocents
* The Price of Silence
* The Shadow of a Lie
* Her Name is a Whisper
* The Girl Who Was Never There
Bonus:
* Use a powerful image or symbol in your title: Broken Mirror, The Mockingbird, The Empty Cradle
Ultimately, the best title will depend on the tone and themes of your story. Consider what feeling you want to evoke in the reader and what best captures the essence of your story.