UPDATE: IAN Thorpe - Australia's greatest Olympian - has gone home after being admitted to a Sydney hospital to fight his decade-long battle with depression and alcohol abuse.

Thorpe is believed to have left hospital care for home early this morning, having been under medical supervision since Wednesday night.

The champion swimmer spent time at Bankstown Hospital and Strathfield Private Hospital in the latest chapter of his grave fight against illness.

After The Daily Telegraph broke the story of Thorpe's hospital admission, beyondblue chief executive Kate Carnell commended the 31-year-old for his bravery in seeking help.

"It is a very brave move from Ian and I commend him for it," she said.

"Far too many people, and particularly men, never take action to get appropriate treatment for depression and can spend their whole lives battling it alone.

"Also, far too many people self-medicate with alcohol, which may provide temporary relief, but can do enormous damage to a person's wellbeing in the long-run.

"As one of the world's greatest swimmers, Ian showed enormous strength, resilience and tenacity, and we all adored him for it.

"Australians loved and supported him when he was winning and he needs our love and support again now."

Family members have revealed Thorpe was injured in a fall earlier this week before they sought medical help, and he was admitted to hospital on Wednesday night.

Today, his manager denied he was in rehab and claimed he was in hospital for a shoulder operation.

Thorpe's struggle - including that failed comeback attempt for the London Olympics - has become the saddest and most heartbreaking story in Australian sport.

The setback has shocked his closest friends, who he has been socialising with since returning to Australia to stay with his parents at their Panania home over Christmas.

The smiling exterior in public has often disguised his private battles with depression and alcohol abuse.

Broadcaster Alan Jones, himself recovering from recent back surgery, is one of Thorpe's closest associates and spoke to the swimming champion recently.

THE COMEBACK: I LOST MY MOJO

IAN THORPE: IN MY OWN WORDS

GALLERY: IAN THORPE

"Yes, it's serious but there's not a lot I can or want to add," Jones said last night, "Ian is a beautiful person but he has difficulty recognising his problems."

Only last week the five-time Olympic gold medallist was spotted at the Australian Open in Melbourne. He appeared happy and cheerful but complained of constant pain from an old back injury.

In his autobiography published last year, Thorpe opened up about his struggles.

"Not even my family is aware that I've spent a lot of my life battling what I can only describe as crippling depression," he wrote.

Timeline: Ian James Thorpe was born on October 13, 1982 1994, starts competing, winning nine gold medals

in the NSW Short Course Age Championships 1998, wins his first of 11 world championships With three gold and two silver medals, he is the most successful athlete of the 2000 Olympic Games At the 2004 Athens Olympics he wins two gold medals, a silver and a bronze After the 2004 Olympics, he decides Ian Thorpe took to take a year off from competitive swimming November 2006, announces his retirement February 2011, says he wants to compete in the 2012 Olympics, but fails in the trials January February 2014, admitted to hospital

In Melbourne last week, Thorpe attended a training session with Melbourne Victory, posing for photos with Socceroo Archie Thompson, who tweeted: "Awesome to meet one of Australia's greatest swimmers."

Thorpe has his own twitter account with almost 100,000 followers but has not used it or Facebook since October.

Last weekend he also attended the wedding of model and long-time friend Tahyna Tozzi at Kurnell in Sydney's south. The next day he was at an Australia Day party with friends in the Shire, including ex-NRL star Jason Stevens.

A close friend of Thorpe last night said the former superstar had been struggling for some time.

"He had an accident at home," the friend told The Daily Telegraph, "He slipped and hurt himself.

"As for the depression, I think his book captured what you're talking about and what has happened recently. We're hoping he's going to be okay and make a full recovery."

In his book, Thorpe revealed how he often turned to alcohol as a release.

"I used alcohol as a means to rid my head of terrible thoughts, as a way of managing my moods," he wrote.

"I did it behind closed doors, where many depressed people choose to fight their demons before they realise they can't do it without help.

"There were numerous occasions as I trained to defend my Olympic titles in Athens that I abused myself this way - always alone and in a mist of disgrace. It's like a weight is pressing down on you. There are days when you just can't get out of bed. You cannot face the world.

"You tell yourself simple things like: 'Just get to the kitchen and get a glass of water.' But not being able to do something so basic is frightening.''

Thorpe has been a resident of Switzerland for 18 months, leaving Australia not long after his failed comeback.

He has a number of major sponsors including adidas, Virgin Australia and Blackmores. He is also under contract to the BBC in the UK.

He has a list of powerful friends and advisors - Alan Jones, Westpac boss Gail Kelly and sports agent James Erskine - who have helped him following failed business ventures. Friends and his management have thrown a protective blanket around him to protect the endorsements.

He lost money on Gold Coast real estate and sold his Cronulla home two years ago.

The hospital refused to confirm Thorpe had been admitted and his agent did not return phone calls.

Readers seeking support and information about depression can contact Lifeline on 13 11 14