The former England midfielder, 45, travelled to a clinic in Arizona earlier this week in a bid to tackle his alcohol addiction.
He suffered a bad reaction to the detox programme he was placed on at the clinic and his former Tottenham team-mate Gary Mabbutt revealed that Gascoigne was moved to the intensive care unit of a local hospital.
Dr John McKeown, a psychotherapist who has worked with Gascoigne for more than 10 years, said in a statement: "Following reports today I feel it's appropriate to bring people up to date on Paul Gascoigne's condition."
The statement continued: "Paul has experienced severe complications with his detoxification. This is not unusual for someone who has been drinking as heavily as he has.
"Paul was transferred from the US Clinic Cottonwood to a local hospital to be monitored so as to be completely satisfied that there are no other complications to his health.
"He is still receiving that care but the hospital has reassured me that he is up and about walking. There are no fears for his life. We will aim to keep everyone concerned updated on a regular basis."
The Sun had reported that Gascoigne was "close to death" after suffering "a catastrophic reaction to alcohol withdrawal", causing his organs to shut down.
Gascoigne travelled to a clinic in Tucson, Arizona, following a shambling and incoherent public appearance in Northampton on January 31.
He was pictured drinking a pint of beer at an airport bar in Phoenix after escaping his minder.
A group of friends including Chris Evans, Gary Lineker and Wayne Rooney had offered to fund Gascoigne's eight-week stay at the clinic, which costs around £30,000.
A source told The Sun: “Gazza’s got no money to pay for the treatment and health care in the US is very expensive.
“His life depends on it.”
Rooney was just starting out on his career at Everton when he had the opportunity to train with Gascoigne, and he said: "It's a shame, of course (Gascoigne's current situation). He was a hero of mine growing up and it's sad for everyone to see and read about."
He added: "My best wishes are with him and hopefully he can get himself out of this situation. I'm sure everyone, every England fan and every Paul Gascoigne fan wishes him the best of luck.
"I trained a couple of times at Everton with him. I was only about 14 or 15 but, of course, for Everton to sign a player of that stature was incredible.
"I was watching him play for England for years so to then have him going to the same place as I was going to train was great and to see some of the stuff he could do with the ball.
"Even though it was towards the end of his career at Everton, he still had a big impact on some games."