What effect does the first-person point of view of the yellow wall-paper most likely have on the reader

"the yellow wallpaper" is written in a first-person point-of-view, with both present- and past-tenses. the narrator writes in present-tense, but recounts conversations and other events in past-tense; this is typical of  epistolary writing, and the tense structure of the story has little to do with the themes.

the first-person narration, however, is vital to the story's impact. by showing the reader a narrator who is suffering deep emotional and mental problems, and who is therefore unreliable, the story becomes less about the factual events and more about the culture of the times. the narrator is essentially held captive against her will; the story becomes more of a prison account than a typical diary. her slow mental breakdown is echoed in the writing, which becomes more and more fragmented as the narrator loses her sanity.  

imparadis't in one anothers arms  

the happier eden, shall enjoy their fill  

of bliss on bliss, while i to hell am thrust,  

where neither joy nor love, but fierce desire,  

among our other torments not the least,  

still unfulfill'd with pain of longing pines;  

yet let me not forget what i have gain'd  

from their own mouths; all is not theirs it seems:  

one fatal tree there stands of knowledge call'd,  

forbidden them to taste: knowledge forbidd'n?  

suspicious, reasonless. why should their lord  

envie them that? can it be sin to know,