It’s a warm day, and when I arrive at her house in the affluent suburb of Monkstown in Dublin, Sinéad O’Connor is sitting on her front step opposite an icon of the Virgin Mary while some men haul out the equipment she’s been using to record her contribution to the soundtrack of The Water Horse, a children’s film due out at the end of the year. She’s wearing scruffy track pants and a paint-splattered fleece top, her head shaved into a soft crop as it has always been but her face older, more tired – thanks mainly to her four-month-old son Yeshua’s sleep patterns. She’s exhausted, she’ll tell me later, “But I don’t mind. He’s just so cute, smiling at you in the middle of the night. And because he’s the last one, you’ve got to appreciate it all, even if you are tired.”

O’Connor turned 40 this year, and if I needed a reminder of how much time has passed since she shot to global fame with Nothing Compares 2 U in 1990, it comes in the shape of the hefty, pleasant-looking guy with extravagant facial hair sitting in the front garden next to her. At first I think he is one of the roadies taking a break, but then I see his arm is in a cast. I ask him how he hurt it, and he laughs and says it was a skating accident, looking up at me with his mother’s huge blue eyes. At 20, Jake is the oldest of O’Connor’s four children, and lives in an annexe behind the large Victorian house where O’Connor lives with the new baby, three-year-old Shane, and her daughter Róisín, aged 11. The rented house has the lived-in look you’d expect of somewhere that houses two large dogs and three small children, but it’s also clean, comfortable and filled with toys, religious icons and trinkets: a home.

Talking to O’Connor, there are two things you notice immediately. First, there’s a vulnerability, despite her apparent toughness. She may be easy to attack from a distance – and indeed, that seems to be the default setting for most of the media – but as we sit down at a table in a sunny side-room just off the huge kitchen and I watch her fidget nervously with her fingers, my immediate instinct is to protect her, to look after her. The other thing you quickly learn is that she lacks an edit switch, and in an interview the main person you want to protect her from is herself. As always she answers questions with disarming honesty, leaving herself wide open to more of the attacks and criticism she so hates. It’s like watching someone complain they’re hot, while continuing to feed the fire.

“Nobody is telling you, ‘Don’t say this’, or ‘Don’t say that’,” she says at one point, explaining how unprepared she was for the fame that overwhelmed her at the age of 23, then adding more thoughtfully, “And you’d probably tell them to go f*** themselves if they were. You shouldn’t have to be in a situation where you can’t be honest if you want to.”

So she will tell me about the new coil she’s started using to ensure that Yeshua really will be her last child, about various ill-advised affairs, about faith, therapy, shoplifting and her frequent thoughts of suicide. Some of this, to be fair, was in answer to my questions; but when I asked about a line in one of her new songs about stealing a Bible, I was expecting to hear about some childhood folly, not to hear that it happened three years ago, and for her to tell me the location of the shop and the exact date. “My manager is completely freaked out about me telling anyone,” she laughs after finishing the story. “But I don’t give a shit.”

She is about to release a new album, Theology, her first to feature new songs for seven years. In 2003, a year after releasing Sean Nos Nua, an album of traditional Irish songs, she announced she was giving up music completely, and apart from an album of reggae cover versions, recorded over a couple of weeks in Jamaica, she has remained silent. When I ask why, she comes up with a variety of answers: her manager of 12 years, Steve Fargnoli, had just died and she didn’t want to replace him. “I got into the pop thing very young – I was 17 when I signed my deal – and I came to feel that I hadn’t formed an identity of my own. I was quite disillusioned, and also, I was tired of carrying the weight of the whole ‘controversial Sinéad O’Connor’ crap. That’s a painful, difficult thing to carry, and I felt I couldn’t work without having to deal with that. So I decided to just come away from it all. I didn’t have a nanny or any help in the house, I just looked after the kids. It was great!”

She occasionally pondered what to do with the rest of her life. But whenever she talked about getting a “normal, regular job”, her friends just laughed. Everyone but her, it seems, knew she’d come back to music eventually. And she has, but first she needed to find her way through something far darker. Ever since she was 23, she says, she’d had thoughts of suicide.

“I began to have this quiet little voice every now and then – although ‘voice’ is the wrong way to put it. It’s your own thoughts just gone completely skew-whiff: ‘Look at that tree, you might hang yourself on it.’ Until the volume went up so loud that I took myself to hospital. There would be nothing wrong in your life, but you’d think about suicide all the time. It was almost funny. But after Shane was born I was really ill, and I was really worried because I was close to actually doing it. So when he was about about five months old, I took myself to hospital.”

She’d been to hospital before, a couple of times, but says they just left her crying in a bed for a week or so before discharging her. She’d also been to various therapists – including one, in London, whom she saw five times a week for well over a year. But this time she was diagnosed with bipolar disorder, or manic depression. O’Connor describes the illness as like having a gaping hole in the centre of her being. She took the drugs she’d been prescribed, she smiles, “And within half an hour it was like cement going over the hole.”

When she gave up music, she got rid of all her instruments. “I never even looked at a guitar, there was nothing in the house.” But straight after leaving the doctor’s office, she bought the piano that now sits in her kitchen. The diagnosis, and then the drugs, gave her back her creativity. It wasn’t all so immediate, she says. Full recovery has taken time, and there have been setbacks: while pregnant with Yeshua she stopped taking the drugs, and afterwards she didn’t go back on them. “I was hoping that perhaps the thing would disappear and I’d be grand, but I wasn’t. So I’ve been back on them now since he was eight weeks.”

It seems to me that her illness could explain much of the behaviour that has got her into trouble over the years. Subsequent revelations have shown she was right to link some elements of the Catholic Church to child abuse, but ripping up a picture of the Pope on live US television probably wasn’t the most career-savvy way to express those concerns, for instance. Yet she isn’t interested in wiping the slate clean. “I don’t want anyone looking at things that Sinéad O’Connor has done – the Pope thing, or any other f***ing thing – and saying that those are the result of being manic depressive, because I don’t believe that. Those are things that I stand by and am proud of and would do again if I had the time over.”

But the suicidal thoughts were part of her illness, she says, and the drugs have taken them away. I point at the tree outside the window. So when you look at that now? She smiles, and it lights up her whole face. “I think, ‘What a gorgeous tree!’” I wonder if she feels angry that so many professionals failed to notice that she was suffering from a treatable medical condition, and she shrugs and says that when she went into therapy she was young, and stupid – and famous, and rich. “I don’t so much get pissed off, I get sad about it.”

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