This continued until she was 13, at which point O'Connor says she ran away from home.
O'Connor also laments about the fact that her own family will not take care of her, while accepting some of the blame for the tense relationship she has with her brood.
"I obviously want to be really careful cause I love my family and I don't blame them," says O'Connor.
"It's not easy for families of mentally ill people. We can be difficult."
She then explains: "What happened was I had been writing to my family begging letters and angry letters and raging and I don't want to make out like I'm a victim here, I give it as good as I get. I thought it might be better if my family, if they saw how I'm feeling, they would relate to it."
O'Connor was hospitalised in early August after telling fans on Facebook that she was suicidal and struggling in her day-to-day life.
The clip soon got the attention of authorities, who after seeing the video did a welfare check on the singer at the $70-a-night Travelodge where she was staying in New Jersey.
Soon after a post appeared on her Facebook page that said the singer was doing better and not in danger of hurting herself.
"Hi everybody, I am posting at Sinead's request, to let everyone who loves her know she is safe, and she is not suicidal," read the post.
"She is surrounded by love and receiving the best of care. She asked for this to be posted knowing you are concerned for her. I won't respond to any questions, so please understand. I hope this comforts those of you were concerned."
Soon after, DailyMail.com revealed that she was receiving hospital care.
That breakdown came against the backdrop of a legal battle where she is being sued by a former lover - and long-term manager - for alleged defamation and breach of contract.
Where to get help
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
Or if you need to talk to someone else:
- LIFELINE: 0800 543 354 (available 24/7)
- SUICIDE CRISIS HELPLINE: 0508 828 865 (0508 TAUTOKO) (available 24/7)
- YOUTHLINE: 0800 376 633
- KIDSLINE: 0800 543 754 (available 24/7)
- WHATSUP: 0800 942 8787 (1pm to 11pm)
- DEPRESSION HELPLINE: 0800 111 757 (available 24/7)
- SAMARITANS: 0800 726 666
- OUTLINE: 0800 688 5463 (confidential service for the LGBTQI+
community, their friends and families)