The 34-year-old loves the spooky dolls like her own children and even gets a baby-sitter to look after them when she goes away.
But Katrin, from Glasgow, says the spirits possessing the dolls are prone to bad behaviour including turning on taps, changing TV channels, hiding keys and she believes they even started a small fire in her home.
Despite their mischievousness, Katrin says she couldn’t bear to be without her creepy companions.
Katrin, who is mum to Christopher Robin, 8, and Karl, 7, explains: “I became interested in the spirit world in 2008, while living in Estonia, because I felt the presence of a spirit. When I moved to Glasgow soon after I started researching spooky things and stumbled upon ‘haunted dolls’.
“The dolls are not possessed as such, the doll is the spirit’s home. The spirit is attached to the doll and sometimes leaves it in the same way humans go to work every day.”
She adds: “You can buy a doll, get it in the post, and the spirit comes with it.”
A shop in Shrewsbury, Shropshire, sells the dolls in the UK and scores of people chat about the subject on forums.
In August 2010 Katrin ordered her first doll, Mystical, from the USA for just £10.
She says: “When she arrived I realised straight away she was not a doll, she was a person. That night the TV switched off and on, the lights flickered and I knew it was Mystical talking to me through the electricity.
“A week later Mystical told me, in the same process through the TV, that she had died when she was 103 and is very wise.”
After coming to terms with Mystical’s powers, she bought more dolls.
She says: “Cost depends on quality and history.
“You can’t put a price on them, because they’re so much more than dolls, they’re links to another world. I am happy to go without other things to buy the dolls. I make my own clothes rather than buy new.”
Katrin believes each doll is a different person who has passed away, and uses the name they had in life.
She uses specialist ghost-hunting equipment to chat to her dolls, including voice recorders.
She says: “I put my phone on record when the dolls are in the room and listen back. You can hear them. They sound like humans, having conversations in the background.”
Michael was the second doll she “adopted” in June 2011. Katrin believes he died of cot death in the 1980 and has since inhabited the body of a porcelain doll.
Not everyone is as keen on the collection as Katrin.
She says: “Usually my sons are not scared by the dolls, they like them and read to them. Some relatives don’t like them, they make them nervous.
“Michael will twist his head. My mum noticed this too, and his facial expression changes. When he sees me playing with my children I often sense him crying out: ‘Mummy, play with me.’ But what do you expect? He is only a child.”
It is not just Michael who plays up.
Katrin says: “Ashley told me she died more than three decades ago in a car crash. She regularly hides my car keys, because of the accident.”
She says each of the dolls has a story.
Katrin doesn’t like to leave the dolls alone, so her mum babysits if she has to go away over night.
She says: “People think I am mad, but I have heard the dolls talk. I have adopted them like I would a child and I would not let them go.”
Haunted dolls cost between £10 and £500 depending on their history.