Why is sleep important for teenagers?

Explanation:

a teenager needs between eight and 10 hours of sleep every night.

Most teens only get about 6.5-7.5 hours sleep per night.  

Chronic sleep deprivation can have effects on a teens life, including affecting their mental wellbeing and reducing their academic performance at school.  

as for symbolic actions, the narrator's tearing down the wallpaper in an attempt to find the "woman" in the wallpaper represents her struggle to retain or regain her sanity.   the wallpaper has been part of her confinement and by her tearing it down, she is freeing herself from that confinement.

i think the literacy device is "it's frozen head"