Hatton's last fight in May 2009 ended with him being knocked out by Pacquiao
Former world boxing champion Ricky Hatton has consulted a rehabilitation specialist following newspaper allegations that he used cocaine.
His spokesman Max Clifford told the Press Association that Hatton has been suffering from severe depression.
"Ricky's father has already been talking to the specialists over the last few weeks," Clifford said.
"He and others have been increasingly concerned about Ricky's depression and his drinking."
Clifford added: "He met with the specialist [on Monday] for four, five, six hours and he was told that his depression is severe and that he has a drink problem.
"The drugs are quite recent and not actually the problem when we're talking about degrees."
Hatton also faces a meeting with the British Boxing Board of Control (BBBC) over the allegations.
Reports claim he could be suspended, fined or have his fight and promoters' licences withdrawn.
"The Board want to see Ricky at the earliest opportunity and discuss the issues raised in the press accounts," said BBBC chairman Charles Giles.
The former two-weight world champion last fought in May 2009 but has never ruled out a return to the ring, a stance he reinforced on 8 September in
a column for the Manchester Evening News.
Hatton renewed his fight licence with the BBBC in July and is also a licensed promoter, representing many of the country's most promising fighters.
"The Board enforces the strictest standards with regard to the use of both recreational and performance enhancing drugs by participants in any capacity in professional boxing," the BBBC said in a statement.
"It is concerned at all times to ensure that the sport is run in the best interests, both of those who take part in boxing and the public interest, and that those involved in professional boxing do nothing to damage the reputation of the sport."
Hatton was said to be "devastated and distraught" after the
News of the World
published video of him allegedly snorting cocaine.
"I spoke to him on Sunday and he's very, very flat. He just feels he's let everybody down," added Clifford.
Since making his professional debut in 1997, Hatton, from Manchester, has won 45 of his 47 fights.
He beat Tony Pep to win the WBU light-welterweight title in May 2001 and added the IBF crown by memorably stopping champion Kostya Tszyu in 2005.
He successfully moved up to welterweight, taking the WBA crown, but was outclassed by Floyd Mayweather in 2007 before being floored three times inside two rounds by Manny Pacquiao in 2009.