George Michael is the latest celebrity to seek treatment for anxiety.
The 49-year-old former Wham! singer cancelled next month's nine-day tour in Australia to seek treatment for the "major anxiety" he said he has suffered since his near-death bout with pneumonia last November.
"I have tried in vain to work my way through the trauma that the doctors who saved my life warned me I would experience," Michael said in a statement on his website. "They recommended complete rest and the type of post-traumatic counselling which is available in cases like mine but I'm afraid I believed (wrongly) that making music and getting out there to perform for the audiences that bring me such joy would be therapy enough in itself."
Instead, the singer said, he "seriously underestimated" how difficult the past year would be.
"Although I was right to believe that the shows would bring me great happiness and that my voice would recover completely (I truly think that some of my recent performances have been my best ever) I was wrong to think I could work my way through the major anxiety that has plagued me since I left Austria last December," he said.
Michael fell ill last November after completing 46 shows of a European tour and spent a month in a Vienna hospital where he was treated for life-threatening pneumonia.
The singer points to his near-death experience as the reason behind his anxiety, but nearly everyone experiences some anxiety -- that feeling of worry before some important event, which can lead to tense muscles, upset stomachs, racing thoughts and pulses, Jonathan Abramowitz, associate chair of the University of North Carolina's psychology department told ABCNews.com.
"When it begins to interfere with a person's performance, cause a great deal of distress or is painful to the point of trouble sleeping, then it crosses the line into a clinical problem," Abramowitz said.
Nearly one in four people suffer from clinical anxiety disorders, including panic attacks -- the rapid onset of anxiety. Some are genetically disposed, Abramowitz said, and sometimes an incident, like Michael's major illness, can trigger an anxiety disorder.
The best treatment is cognitive behavioral therapy, which helps patients develop skills they can use in anxiety-provoking situations, Abramowitz said. Medication can also be helpful as a short term solution.
Michael is by no means the first star to take a break because of anxiety. About a month ago, LeAnn Rimes announced she had checked into a treatment center for help with anxiety and stress. Click through to read about Rimes and others.
In August, country crooner Rimes checked into a treatment center, seeking emotional help.
"LeAnn has voluntarily entered a 30-day in-patient treatment facility to cope with anxiety and stress," her rep, Marcel Pariseau, told ABC News in a statement. "While there will be speculation regarding her treatment, she is simply there to learn and develop coping mechanisms. While privacy isn't expected, it's certainly appreciated."
The "Blue" singer checked into the facility Aug. 29, the day after her 30th birthday, and spoke candidly with People about seeking treatment.
"This is just a time for me to emotionally check out for a second and take care of myself and come back in 30 days as the best 30-year-old woman I can be," she told the magazine. "All the things in my life will be there when I get out, but you know what? I'm hoping they're not going to affect me as much," she said. "I'll have the tools to know how to deal with them."
In the last year, Stone has become America's golden girl, staring in major films including "The Help," "Crazy. Stupid. Love" and "The Amazing Spider-Man." But the actress opened up to Vogue in its July issue about her history with panic attacks that began when she was eight years old.
"I was just kind of immobilized by it," she told the magazine. "I didn't want to go to my friends' houses or hang out with anybody, and nobody really understood."
After years of therapy, Stone, 23, was able to work through her fears and start her acting career, but she still gets attacks from time to time. She recently told Interview magazine about her anxiety in filming "Easy A," her first leading role. The actress admitted she has never seen the film because it brings back bad memories of her anxiety.
"I was a wreck during that. I didn't sleep much," she said in Interview magazine. "I remember the day I wrapped 'Easy A.' Getting into the car as the sun was coming up because it had been a night shoot... It felt like a house had been lifted off of me. I felt a great deal of pressure making that movie, because in my personal life at the time, too, things were just... It was like a hurricane."
British pop soul diva Adele is one of music's biggest stars, but don't expect her to play at the world's biggest music events or stages.
"I'm scared of audiences," she told Rolling Stone magazine last year. "One show in Amsterdam I was so nervous, I escaped out the fire exit. I've thrown up a couple of times. Once in Brussels, I projectile vomited on someone. I just gotta bear it. But I don't like touring. I have anxiety attacks a lot."
Other celebrities freak her out too. "I was about to meet Beyoncé and I had a full-blown anxiety attack," Adele told the magazine. "Then she popped in looking gorgeous, and said, 'You're amazing! When I listen to you I feel like I'm listening to God.'"
Later, when she found herself crying hysterically on a balcony during a fit of anxiety, Adele said she thought: "What would [Beyoncé's alter ego] Sasha Fierce do?" That's when Adele said she came up with her own alter ego, Sasha Carter, the composite of Sasha Fierce and late country icon June Carter, to help her overcome her fears.
Oscar-winning actress Kim Basinger has dealt with anxiety ever since childhood.
"When I was a child, I remember the fourth grade, my mother had to call my teacher in the summer because I had problems sleeping with the anticipation of school coming in September," Basinger told Charlie Rose in May 2000. "She had to ask my teacher not to make me stand up and read or I would faint. That did happen to me one day. ... I knew the words but I would just break out it in a sweat and shake. I don't know where that self-consciousness has come from but it's been there ever since I was a kid."
Basinger calls it "a card I was dealt in my life." Before interviews and appearances, she has to psyche herself up.
"I have to really go through a whole therapy thing in my mind," she told Rose. "I have a motto: 'I'm afraid but do it anyway.'"
Guadagnino was always seen on "Jersey Shore" fist-pumping and bringing girls home to the "smush room," but he got serious on a January episode of the MTV hit when he admitted he was dealing with a lifelong struggle with clinical anxiety. His battle with anxiety forced him to the leave the show temporarily and return home to Staten Island.
"I would have panic attacks from a young age especially in high school," he said in a video for The Jed Foundation, a national non-profit that aims to protect the emotional health of teenagers and college students. "When my anxiety starts to interfere with my job, my school, or things that I do in my every day life, it starts to become a problem."
Guadagnino opened up about his battle with anxiety last April in his tell-all book, "Control the Crazy: My Plan to Stop Stressing, Avoid Drama, and Maintain Inner Cool." The reality star shares tips on how to handle anxiety and why he decided to talk about his disorder.
"Part of healing and going through life in general is getting through tough things," Guadagnino told MTV. "No matter how tough it was — I don't care if it was the worst experience of my life at the time — getting through it is an accomplishment."Vinny from MTV's "Jersey Shore" left the show before its fifth season because of anxiety.
Osmond was never a stranger to show business. His career in the limelight began at when he was five years old, singing on the "Andy Williams Show." But the singer struggled to transition into adult stardom. In his 2006 memoir, he opened up about his battle with anxiety after all his years in the spotlight.
"With success came an ever-growing burden of responsibility," Osmond wrote. "I lived with a near-constant low-level anxiety that I would make a mistake that would not only threaten my career, but also my brothers' — not to mention the livelihoods of many people who work with us or for us."
He later talked to Dr. Phi about his panic attacks. He said some would leave him in the corner of a room in a fetal position.
"I had to seek professional help and medication," he says. "But it never leaves you because it's part of your personality. I've learned not to beat myself up about it. It's OK to make a mistake."
Barbra Streisand is infamous for having avoided live performances for nearly three decades due to a debilitating bout of stage fright.
She told Diane Sawyer in 2005 that she traced her phobia to a concert in New York's Central Park in 1967, during which she forgot the lyrics to one of her songs. She described the experience as "staggering."
"I couldn't come out of it. ... It was shocking to me to forget the words. So, I didn't have any sense of humor about it," she told Sawyer. "You know, I didn't make up words ... some performers really do well when they forget the words. They forget the words all the time, but they somehow have humor about it. I remember I didn't have a sense of humor about it. I was quite shocked."
Added Streisand, "I didn't sing and charge people for 27 years because of that night ... I was like, 'God, I don't know. What if I forget the words again?'"
Streisand returned to the stage in the early 1990s.