Image copyright Catherine Simpson Image caption Catherine and Tricia posed for this school photo in 1973

"My memoir is intensely personal and I've lost sleep over that - I don't feel like I'm putting my head above the parapet - I am dancing naked on the parapet," says Catherine Simpson.

She's wearing a red leather jacket, which belonged to her younger sister Tricia.

Tricia took her own life aged 46 in 2013 after years of mental illness, including depression and paranoia.

Catherine's book, When I Had a Little Sister, is an outpouring of emotions and vivid recollections, as she tries to piece together why her sister died.

She recalls scuttling around with her sisters at the farm where they grew up, playing with stray cats, dressing up in the barn, her Dad herding the cows and her Mum's legendary cooking.

But she also delves deep into generations of a "farming family who never spoke", laying bare the "very repressed atmosphere" at home, where talking about feelings - and what was happening to Tricia's mental health - were not up for discussion.

Image copyright Catherine Simpson Image caption Catherine Simpson's book cover shows an old family photo of her crying over a dead bird alongside Tricia

"My parents loved me, I know they did... but it was a different time and a different place," she says, alluding to her Mum discouraging personal conversations before they could start.

Writing about her childhood on a Lancashire dairy farm, Catherine's story is revealing, not just about her family, but the objects which defined them.

The house was stuffed full of clutter, left there by generations of people who had died.

Each item tells a story, from her mother's endless household gadgets to the stash of Tricia's diaries, which revealed a separate life outside the farmhouse.

The objects appear to be substitutes for the meaningful conversations which were never allowed to take place.

Image copyright Catherine Simpson Image caption Tricia left a huge pile of diaries her family had no idea she had been writing

"It felt like a journey - it was an excavation, an archaeological dig," Catherine says of her trawl through her family's history.

Part of this involved raking through the farmhouse and reusing, recycling or burning everything stored there.

"I felt as though I was digging through layers and layers of years of stories and lives. And just trying to get to the bottom of it, while trying to understand it."

She approves of Japanese tidying guru Marie Kondo, whose series on Netflix recently premiered.

"I like the idea of her thanking objects before you get rid of them. Getting rid of clutter is the first step to liberating yourself," she says.

"We were smothered by stuff and it felt enormously liberating to be emptying the farmhouse."

Catherine initially didn't include anything about herself in the book, but after advice from a writing mentor, she decided to write about leaving home and becoming a journalist.

She also wrote about her own mental health issues.

Media playback is unsupported on your device Media caption How should we talk about mental health?

"I redrafted the book and included my own experiences with depression, and that felt a lot better to me because I thought 'I'm exposing Tricia and she didn't give her permission'."

She sees the memoir as a "tribute to Tricia - about how lovely she was, how much we loved her and how tragic it was. It's not passing judgement on her in any way".

The impact of Tricia's suicide left Catherine, their eldest sister Elizabeth and their dad with a "maelstrom of feelings".

"You never recover - you can never be the same person that you were before," she says. But writing her book and the passage of time have helped.

"I don't cry every day now like I did for months and months.

"I never felt angry towards her, but going back over it all did help with the sequence of events, and how it led up to the point it did."

She recounts how the NHS report on Tricia's death was "so bafflingly written" and full of jargon. It was only when she reread it for the book that she was able to decipher it.

"She thought she was never going to be well. She thought she was a burden to us and those were the two things that came together. Kind of makes me understand why she did it. I've never blamed her. "

Image copyright Catherine Simpson Image caption The sisters shared a sense of humour which is evident in Catherine's writing

Catherine also speaks about the trepidation she felt reading Tricia's diaries, admitting she was "frightened of being criticised in them and too frightened of reading about her depression".

It turned out to be the opposite.

"I realised there were moments of joy in there and there was no criticism of me, in fact there was actually quite a lot of affection towards me."

Her book felt like "a joint project with Tricia".

"The diaries smelt of her because she was a heavy smoker, it was there in her handwriting, all her thoughts and feelings on events I knew nothing about."

Listening to the music Tricia mentioned in her diaries as she wrote, such as Ray Charles, Dixie Chicks and Puccini, Catherine says it "felt like I was there with her, and it carried on feeling like that for the whole two years I was writing the book".

Image copyright Catherine Simpson Image caption Happier times: Catherine and Tricia at home

She cried when she handed the finished article to her literary agent.

"I really wrote the book for myself originally," she says, but she realises it may help other people trying to navigate the NHS for help with mental health issues.

Tricia's mental health problems developed during her teens but were not recognised until she was older.

"People are talking more and more about mental health now, thankfully they are," she says.

"I hope the book encourages families to start conversations early, because we ended up living from crisis to crisis. When it was impossible at that stage, we hadn't built up a foundation of talking," she adds.

One of her biggest realisations about Tricia's suicide came after the book was finished.

She describes the "horrible" compulsion to "fix" Tricia because "you're so worried about what's going to happen if you don't".

Helping someone in distress

"I would say to people who have had a family member like Tricia 'be there for them and don't talk if that's necessary'.

"Because we didn't have this culture of meaningful talking, it was all 'have you been to the doctor, have you taken your medication, why don't you try this?'

"Not helpful.

"What I should've been doing when she was really severely ill was just being there, giving her space to be who she was. Indicating that she was good enough. That we loved her regardless. And that we were there whenever she needed us."

She says she never asked Tricia the questions which "doctors now encourage you to ask", which are "do you feel suicidal? Do you have a plan?"

Catherine and her family didn't ask because they thought it ' might topple her over the edge and might suggest something that hasn't even occurred to her".

'We're all human'

Now, having written the book, Catherine says it definitely "helped" her come to terms with her family's past.

"It helped me understand my family a lot better and I began to see my mother in a different light.

"I thought I was writing a book about Trisha and then I realised I was writing a book about my Mum.

"I think it made me more accepting of people, because life is very complicated. We're all human, we're are all struggling through this life the best we can.

"No one chooses where you are born, we have no choice about where we born or the culture were born into. And my Mum did her best. Really."

'We have a brilliant relationship'

But despite so much pain, she says "mental health is far from a taboo subject in our house".

"There is nothing that is not on the agenda," she says.

She and her husband have two daughters aged 21 and 23.

"My daughters tell me all sorts, although I presume they don't tell me everything because they're young women doing their own thing - they don't tell me about the tattoos until after they've had them...

"But we have a brilliant relationship actually - it's based on talking."

When I Had a Little Sister is out now.

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