Rumer reveals the darker side of success

On paper, it looks like a perfect year. What she describes, as she sips sugary tea in her dressing room at the Manchester Apollo, sounds more like a nightmare. "Suddenly I was cut off from my environment. It was like being murdered. I didn't know who I was. It was extremely traumatic," she says in disconcertingly businesslike tones.

I'd already heard about Rumer's disarming openness. Born Sarah Joyce into an English family 32 years ago in Pakistan, she discovered at the age of 10 that her real father was their Pakistani cook - a story she detailed in her first press biography sheet. She has talked frankly about her mother's struggles with mental illness and death from breast cancer in 2003, of her parents' divorce, and of her journey to Pakistan to find her real father only to be told that he had died just months before her arrival.

Even so, what she says mere moments after we sit down comes as a shock. "To be honest with you, I was not grafting hard this year so much as surviving. It was just I wasn't well. I've just been diagnosed with manic depression and ADHD and post-traumatic stress disorder. I've been ill for years and too scatty to sort myself out."

Her problems were physical too. "I had all sorts of respiratory problems. Stress makes you ill and I was so ill. I couldn't cope. There are patches that I can't remember." She goes on to describe her lowest point: "It all came to a head when I was in Dunkeld in Scotland [in August this year] and I did this gig with a respiratory infection.

I was deaf in one ear and the place was really dark and gloomy and dusty. I was deaf, dumb and blind on a stage in front of hundreds of people and I got the biggest panic attack. Then this fly comes in and starts to fly around the microphone, and I'm overjoyed to see the fly, and I think to myself, 'I'm so lonely'. Do you know what I mean?" She begins to cry.

There has been plenty of debate lately about the effect of intense fame on the emotionally vulnerable (Susan Boyle), those struggling with addictions (Amy Winehouse) or with serious mental health problems (Adam Ant). To an outsider, Rumer would appear to be operating at the pleasant end of the music industry. She has had real success and serious critical acclaim without household name status or the lurid attentions of tabloids and gossip mags. The strength of mind required to cope even at this level must be far greater than we might have assumed.

However, she is telling me all this, she says, to emphasise that she has turned a corner. Psychiatric drugs have "taken the terror away from life", she says. She also recently changed her management company and will not be rushed to make a second album. "I have beautiful people around me now. Angels."

In the meantime, I'd prescribe Seasons of My Soul to anyone with a case of the blues. The tone is soft and sweet. The languorous ballads are sung in a voice that could defrost your freezer. When it was released last November on Atlantic, it caught many by surprise. Superficially, it sounded like the same mum-friendly supper jazz - but it contains a heartache that lingers, quietly demanding a deeper response from the listener.

Carole King and Laura Nyro are obvious influences, and she sings like Karen Carpenter. However, while many contemporary singers are content to pastiche, Rumer's work deserves to sit alongside that of her predecessors. Despite being born at the end of that decade, Rumer can out-Seventies them all. At her Manchester concert, she includes impeccably chosen covers of Nyro's American Dove, King's Being at War with Each Other, Joni Mitchell's Free Man in Paris and Stephen Bishop's Little Italy.

As a concession to those with less knowledge of the era's great female singer-songwriters, she performs Elton John's Rocket Man. It's a hushed gig and the music rarely picks up the pace (you wouldn't like to be her drummer). Yet the atmosphere she creates with that blissful voice is mesmerising.

In the afternoon, she plays me snippets from her next release, Boys Don't Cry, a collection of covers by male singer-songwriters of the Seventies, due for release in late February ahead of her second album proper. She doesn't want me to reveal the track listing, but the presence of artists such as Isaac Hayes, Clifford T Ward, Tim Hardin, Todd Rundgren, Gilbert O'Sullivan and Townes Van Zandt will have musos of a certain vintage putting a big circle in their 2012 calendars.

With typically lush production, it's all so beautiful that I want to grab her laptop and run off down the street with it.

"It's a passion project for me, all these songs by gnarly old guys that killed themselves," she tells me, generalising somewhat. As the sun sinks and no one bothers to turn a light on, she talks about her admiration for more modern artists such as Adele ("She's so young! When I think of all the crap I was writing at 21 ") and Duffy ("She's tough. Girls like that who dream their way out of small villages have all my respect").

For her part, she's glad that she has a few years of odd-jobbing life experience on them. "I'm grateful that I'm older. I'm in a better place now. I've adjusted to this life, I've changed gears and I'm ready to embrace it." Treat her carefully, world - she's one of the most precious singers we have.

Rumer plays the Albert Hall, SW7 (020 7589 8212, royalalberthall.com) on Tuesday 22 November