Edgar Allen Poe

After finishing several Edgar Allen Poe stories I was left with a lot of unanswered questions. Why was it always about a man who would go mad? And then why did he result his madness in violence and slaughter? I knew a lot of things about Poe due to my gruesome fascination with him since the age of six but to me Poe's greatest mystery remains himself. In one story he writes of a man who looses his mind  and kills an old man with the defense that the old man's eye was haunting him, and then hides the body in the floor of the old man's home. And in another story he writes of a younger man who takes in a black cat, and in a violence rage blinds the cat in one eye. Later the man again believes the eye is haunting him and kills the cat and hides it in the basement walls. My first thought was "whats this guys deal with eyes?" and "why does he kill things and bury the bodies in houses? whats wrong with a with like not burying bodies in your house? Does he want to be haunted or something?". But then I began to see the reoccurring situations in these two stories: the eyes, the madness, the murder and then the covering of the murders. What was the significance of these things? What message was Poe trying to get across to the reader? Poe once said "I became insane, with long intervals of horrible sanity," was his writing his way of expresses his madness with no physical violence? Was he voicing his own life experiences through reoccurring things in his story? But if it was madness he wanted to seek out why didn't he just look into his own life. I mean he married his 12 year old first cousin when he was 24. Is that not creepy enough for him? And those weren't the only abnormal aspects in his life there were so. Many. More. In Poe's journey to make and create mysteries the greatest mystery he made was himself.