When Rolando Villazón steps on to the Vienna Staatsoper stage this week to sing Werther, the opera world will breathe a cautious sigh of relief. One of its most bankable stars is back from a six-month absence blamed variously on depression, voice problems and ill-health.

Last year was a tough year for opera: cancellations broke out like bubonic plague and singers began to stamp their feet about overwork causing stress and illness. There is certainly some truth to this claim. But can the opera community act to prevent another year of no-shows? In a world driven by extraordinary ambition, ruthless competition and ego, that sounds unrealistic.

Opera has already survived its whistle-blower moment; the German tenor Endrik Wottrich – criticised for pulling out of Die Walküre at the Bayreuth Festival last summer with a cold – claimed that stressed opera stars were resorting to drugs and alcohol to perform.

But ask around for a Verdian Amy Winehouse and you’ll probably be disappointed. Few singers acknowledge taking anything stronger than vitamins and echinacea to fight off colds, though some use beta blockers to control nerves. “In the old days it was alcohol,” says the English bass Sir John Tomlinson, now in his fourth decade on stage. “There were singers who had a bottle behind the dressing room radiator. Now you see quite a bit of pill-popping.”

Opera has always been star-driven. But today’s big names are brands; they have CDs to promote, DVDs to plug and lucrative endorsements – all besides the day job. Jürgen Flimm, the artistic director of the Salzburg Festival, thinks this off-stage circus is a problem. “Plácido Domingo told me: ‘Before, we concentrate on singing and between the performances we rest.’ No TV, no interviews, no merchandising. But now you have to advertise the watch and the jewels.” Anna Netrebko promotes Chopard jewellery as well as O phones; Villazón advertises Rolex.

After a festival beset by cancellations – Villazón, Netrebko, Neil Shicoff and Magdalena Kozena all pulled out – Flimm believes that today’s singers overperform, cramming every possible opera and recital into already hectic transatlantic schedules. “They are singing too much,” he says, and gives the example of the Swedish tenor Lars-Erik Jonsson, who died in May 2006 at 46. “He flew all the time. They say he was much longer in the air than on the stage. So this is dangerous.”

One manager likens the opera treadmill to the international tennis circuit, travelling alone without family or friends to share your triumphs and disasters. Opera’s elite see their performing lives mapped out years in advance. The Royal Opera House, for instance, is already booking soloists for its 2014 season. With preparation time constantly squeezed, the American mezzo Joyce DiDonato now uses Skype (the online phone service) to hold “face to face” singing lessons with her teacher, wherever she is in the world. She recently took a seven-week sabbatical after performing six new roles in the past two years.

“ Der Rosenkavalier [for San Francisco Opera in June] was role number five in 18 months,” she says, “and I was about two months behind where I wanted to be when I arrived the first day.” One house had changed its schedule, slotting in Strauss’s Ariadne auf Naxos when DiDonato had planned to take time off. Singing her first Strauss was good preparation for Rosenkavalier, but it derailed her groundwork for the role of Octavian. “I was looking at Mount Everest, going ‘I need oxygen’,” she says.

From the comfort of the stalls it is also easy to forget the physical toll of performing. Producing three hours plus of faultless vocal gymnastics furiously dehydrates the body and, with the demise of “stand and deliver” opera, directors demand more from their cast. Keith Warner’s recent Ringcycle at Covent Garden was a mass of steep ramps and extreme lighting, which almost got the better of Sir John Tomlinson.

“I don’t know about using the word dangerous, but it was risky,” says Tomlinson, 61, who switched from singing Hagen in half the cycle to replacing Bryn Terfel as Wotan in each performance. “One evening, because of the lighting, I literally walked off the front of the stage. I dropped a couple of feet and landed in a heap. Of course everybody thought it was part of the production.”

But are the costs of not performing so great that singers still go on, even when ill? Drafted in as Wotan with only four weeks to curtain up – and barely six weeks before he sang Gurnemanz in another Wagner epic, Parsifal – Tomlinson felt he simply could not fall ill. “I had to be superhuman; there had already been one cancellation.” Besides, if you are ill, he explains, “there’s always a doctor who will prescribe steroids. [Cortisone reduces swollen vocal muscles in the short term.] And there’s always a company who phones up the doctor and says: ‘Get this guy on the stage’.”

Wottrich’s claims about singers’ drug abuse, though, amazed the author Blair Tindall. A former professional oboist, her book Mozart in the Jungle: Sex, Drugs and Classical Music is an exposé of orchestral life in all its orgiastic glory. But she thinks that singers are different.

“Opera singers are characteristically obsessed with caring for their voices,” she says. “Doing drugs and drinking would be like pouring petrol on a Stradivarius.”

But surely if singers simply admitted when they were ill, they could help themselves and support each other in the process. The French soprano Natalie Dessay is rare for speaking frankly about the surgery she had six years ago to remove nodes on her vocal cords. To date, Villazón’s official website makes no mention of the Mexican tenor’s recent troubles, as if the mere hint of vocal weakness might strip the lustre from those top Cs.

Perhaps this is because, in a solitary, tough profession, singers talk of doors being closed to problems. Performers must deal with anxieties, nerves, stress, depression or family issues without a support network. “There is some mentality that we singers are machines and we should always be able to produce,” DiDonato says. “It takes a lot of courage to stand up to a major theatre and say: ‘I cannot do this.’ It should be the priority of the theatres to support singers in those situations.”

Elaine Padmore, director of opera at Covent Garden, sympathises. “We know the stress that singers are under: they’re nervous; they may be doing a role for the first time,” she says. “At the same time, their choice of profession is one that puts them under strain. The show’s the thing and you’ve got to get there.”

Yet companies have their audiences to consider, many of whom pay to see a Villazón, Juan Diego Flórez or Netrebko perform. As Padmore explains, houses employ artists in good faith and expect them to be fit for productions. “It’s the managers who have a lot to answer for if their artists arrive and they’re tired or putting off an illness.”

It is a little too convenient, however, to condemn pushy managers. Simon Goldstone at IMG Artists, whose roster includes Villazón and Danielle de Niese, says that successful performers survive by pacing themselves and being highly disciplined. “Singers should know their limits,” he says. Artists agree. Joyce DiDonato says candidly of her frantic 18 months: “I made the decision to take those roles freely; it wasn’t the manager; it wasn’t the theatre. All singers – we’re responsible for our decisions.”

With so many conflicting interests at stake, in reality it seems that singers must look after number one. As Tomlinson says, “Each performer has the duty of looking after themselves. It’s important to stick fast to your intuition.”

Unfortunately, for the fainthearted in a ruthless world and the overambitious in a competitive one, drugs may be a quicker fix.

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