Over three-quarters of professional footballers in England and Scotland believe depression is a problem in the sport, according to a survey published in British magazine FourFourTwo on Wednesday.
The survey of 100 players, undertaken just over a year after the apparent suicide of Wales manager Gary Speed, who suffered from depression, suggested the illness is more widespread in professional football than previously thought.
An unnamed League One (third-tier) player told the magazine: "It can affect a lot of players. I know because I have been there.
"The easy route was to give up the game completely -- I was in a dark place."
The chief executive of the Professional Footballers' Association (PFA), Gordon Taylor, said his organisation was putting systems in place to tackle depression.
"It is an issue we have been dealing with now for some time and we are looking to ensure that people are aware of what support systems there are," he told Britain's Press Association.
"We have a network of advisers and our own counselling service at the PFA as well."
The survey also revealed that 26 percent of those questioned had witnessed racism in the game, while 14 percent said they thought match-fixing took place, without specifying at which level.
Of those questioned, 43 percent said there were too many foreign players in English football and 62 percent said an openly gay player would not be forced out of the game.
Half of the respondents said that professional players used recreational drugs, but only 13 percent thought performance-enhancing drugs were taken.