Why is Jane imprisoned in the attic in the first place?
The woman in "The Yellow Wallpaper" is suffering from post-partum depression. At that time, the treatments for things like depression were very different from what we have today. Women were often prescribed bed rest, quiet, and solitude to help them recover. Sometimes, women were even asked to eat animal fats and drink strange (by today's standards) concoctions. The doctor for the woman in the story thinks she will get better if she avoids mental simulation like reading or writing. Of course, we now know that staying in bed and having no distractions but thinking are not the most helpful things for depressed patients. The woman's husband and her doctor persist in this line of supposed treatment until the woman basically goes insane.