An oldie - The Yellow Wallpaper simified - I found these when looking for something else (my usual mo) If you are not familiar with Charlotte Perkins Gilman’s short story, it is a classic 19th century mad woman in the attic story. The twist is that it is told from the woman’s viewpoint.
In brief, a young woman is prescribed a “rest cure” by her physician husband. The “cure” takes place in a remote country house with bars on the windows and a horrid yellow wallpaper on wall. She left in the room alone for hours on end forbidden to read or write (though does write secretly). The cure is basically is a form of sensory deprivation and she begins to hallucinate. Woman appear to her hiding in the pattern of the wallpaper and resolves to free them.
Needless to day the “cure” doesn’t have the effect that her husband thought it would.
The story is in the public domain and can be downloaded from google books and other epub sources.