Ricky Hatton says depression almost drove him to suicide after he was knocked out by Manny Pacquiao in 2009.
In an exclusive interview on BBC Radio 5 live, Hatton explained how his life spiralled out of control in a battle with drink and drugs.
Hatton confirmed his retirement in July and now runs a successful promoting business.
But he said: "I was so down, I was crying and breaking out and contemplating suicide."
Hatton lost to Manny Pacquiao in Las Vegas in May 2009 with a brutal second-round knockout.
He said: "I was going deeper and deeper into depression.
"I was getting depressed. I was going out and having a few drinks. The worst thing you can do with depression is add alcohol to it.
"I needed something to get my backside into gear and pull my finger out. Sometimes you have to hit rock bottom to think, 'Blimey Ricky, get a grip'.
"Depression is a serious thing and, after my defeat to Manny Pacquiao, I contemplated retirement and didn't cope with it very well."
The former boxer's predicament was exposed in a newspaper sting where he was shown taking cocaine.
Hatton added: "For someone in my position taking drugs once is nothing short of disgraceful.
"The reason behind my actions and the way I was behaving wasn't a drink or drugs thing, it was depression. I was so down, I was crying and breaking out and contemplating suicide.
"Half the things I was doing I didn't even read about in the paper. I can't even remember the night it happened - that's what depression does to you.
"I was having blackouts, days on end whether I was drinking or not when I couldn't remember what had happened in my life.
"I thank the News of the World because who knows where it could have ended up.
"A lot of people say, 'I've tried committing suicide' - but there's saying it and doing it and it was coming on a regular basis.
"Being a proud man and a warrior, to get splattered in two rounds like I did, was really hard to come to terms with.
"When I tried to get back into training, I realised the hunger was gone and my career was over.
"Everything got on top of me and it was a really horrible time in my life. I would go out, have a few drinks, start sulking and start feeling sorry for myself.
"I kept coming home and crying to my girlfriend saying, 'I want to end it, I don't want to live'.
"Depression is a very serious thing. People don't realise how deadly it can be."
You can hear more of this interview on BBC Radio 5 live Breakfast on Friday, 30 September 2011.
RICKY HATTON'S CAREER
Born Stockport, 6 Oct 1978
Turns pro in 1997
21 fights unbeaten and becomes British light-welterweight champion in 2000
Wins WBU light-welterweight title in 2001
Beats IBF light-welterweight champion Kostya Tszyu by TKO in Manchester in 2005
Points victory over Luis Collazo in 2006 sees him become WBA welterweight champion
Awarded an MBE but loses first fight in December 2007 - knocked out by Floyd Mayweather Jr
Beats Juan Lazcano and Paulie Malignaggi in 2008 but knocked out by Manny Pacquiao in May 2009