Kerry Katona wiped away tears as she watched her foster parents describe her troubled childhood in MTV One documentary Kerry Katona: What's The Problem?, launched today.

Breaking down: Kerry Katona

The 28-year-old allowed cameras to follow her after the outcry caused by her appearance on ITV's This Morning, when hosts Fern Britton and Philip Scofield pointed out she was slurring her words and asked her whether she had been drinking alcohol.

Describing this incident during the first episode of the MTV programme, Katona says: "I felt ashamed, embarrassed, I thought 'Oh my god, you're a disgrace, you need help'. It was purely down to medication, I swear on my children's lives."

During the new series she says she is on new medication which prevents her from slurring, and talks to mental health experts, such as Professor Nick Craddock at Cardiff University, in an attempt to explain her bipolar disorder.

"She knows she's nuts, she's just got to find out why she's nuts," her husband Mark Croft says.

After describing her symptoms, such as feeling elated and feeling paranoid, to Professor Craddock, she asks "Am I nuts?"

"You're not nuts. You're definitely bipolar and a lot of the things you've described are things that other people with bipolar also experience," he replies.

Katona, who won I'm A Celebrity... Get Me Out Of Here! in 2004 and was previously married to former Westlife member Brian McFadden, also explores her childhood trauma and the issues she thinks may have triggered her mental health problems.

Talking to her step-sister Pat Ferrier, Katona describes how, aged three, she found out about her mother's suicide attempts.

"I remember my mother slitting her wrists from I was about three," she says.

The former member of Atomic Kitten also visits her foster parents Fred and Margaret Woodall, who describe what she was like as a teenager.

Showing off her former bedroom to the cameras Katona says: "I used to sleep a lot and looking back now, I do sleep through depression and I wonder whether that's where it all started".

Mr Woodall says: "I always thought you only came into care when you were 13, something like that, but you weren't really, you were in refuges before, this was going on your whole life really, no wonder you were traumatised."

"You've always been the type, Kerry, to laugh things off, look at it as if it were a joke, you've never dwelled on the problems you've had in the past".

In tears, Katona says to them: "I wonder what I've done so wrong, going from being Queen of the Jungle to having a family, to being the most hated person in Britain."

Watching the programme from the front row, Katona - who had been laughing and joking with her husband until that point-appeared subdued and wiped away a few tears.

Katona also kept quiet as she watched the moment her mother, Sue Katona, turned up at her house for a birthday party.

As Katona's daughter Heidi celebrates her second birthday, she and her mother row in the garden.

Katona also appeared shocked at the amount she swore during the filming.

"I have to stop swearing, I swear too much," she told Croft during the screening.

Katona added: "I'm going to hibernate for the next two months."

Kerry Katona: What's the Problem? is on MTV One on Sunday May 17 at 10pm.