The former soap star's mum Margaret lost her battle with breast cancer two decades ago when the actress was just 23.
Now Patsy has admitted she found it difficult to cope with the final stages of her mum's illness.
Writing in her autobiography Absolute Beginner, Liam Gallagher's ex said: "That night she was violently ill. She started throwing up and she couldn't stop and then she began vomiting blood and I couldn't look.
"I felt so ashamed of myself afterwards - what kind of person was I that I couldn't look at my own mum?"
The next day, Patsy headed off to an audition which was where she was when she found out her mum had died.
"I'd wanted to be with her to hold her hand when she died. I've never got over the guilt of not being with her."
In her autobiography, Patsy, 46, explained that after visiting her mum's body, she struggled to cope and found herself turning to sedatives for comfort.
But it was a 'visit' from her mum's spirit which helped her put her mind at rest.
Patsy described her mum appearing in front of her a couple of nights after she passed away, where Margaret explained that she felt relief that her long battle was over.
And while the soap star admits the vision of her mother could have easily been her imagination or a coping mechanism, Patsy felt that Margaret had truly found peace.
The actress went into the Celebrity Big Brother house last Wednesday where she admitted she might be a problem for her fellow contestants.
She said: "I think this a real test of how mentally tough you are."
More on Parentdish: We talk to Patsy Kensit