One in four professional footballers said they suffer symptoms of anxiety and depression in a new study into the sport's largely unexplored ''dark side'' of mental illness.
The mental health of recently retired professional footballers was even more worrisome, with one in three reporting signs of anxiety and depression.
Some 300 current and former professionals - from the Netherlands, Major League Soccer, Scotland, Ireland, Australia and New Zealand - took part in the study for the players' union, FIFPro.
While football can draw on reams of scientific study about players' physical injuries, little research has previously been done into their mental health, and mental health problems have remained very much taboo in the sport, FIFPro chief medical officer Vincent Gouttebarge said.
''There is definitely some dark side of professional football,'' he said in an interview.
''We don't talk about mental health issues in football, or we didn't talk about this issue,'' he added. ''It's quite a macho culture so people do not talk about it.''
Gouttebarge said the study's findings suggest that professional footballers are no less prone to mental illness than other younger people in the general population. He said that might surprise fans who believe footballers live comfortable, worry-free lives, with media attention often focusing on the wealth of the most successful players.
''Contrary to what people think, professional footballers experience psychological problems just like other groups in the population,'' Gouttebarge said.
Among the 180 active footballers who responded to the lengthy questionnaire, 10 percent reported symptoms of distress, five percent reported signs of burnout and three percent said they suffered from low self-esteem. Nearly 20 percent reported problems with alcohol, which Gouttebarge said could include binge drinking and regularly drinking too much, and seven percent said they smoked.
The 121 former professionals who responded on average had 12-year playing careers and have been retired for five years. Fifteen percent showed signs of burnout and 18 percent signs of distress. One in three reported drinking problems, 12 percent smoked, and 39 percent reported suffering from depression and anxiety. Gouttebarge said that could include worrying, mood swings, difficulties sleeping, feeling stressed, not being sociable or a combination of symptoms.
''Mental illness seems to occur among former professional footballers more often than in current players, and more often than in other populations. Consequently, mental illness among former professional footballers cannot be underestimated and should be a subject of interest for all stakeholders in football,'' the study said.
Retirement was ''really a critical period,'' with players abruptly losing the structure of regular training and the support of being in a club, Gouttebarge said.
''You have to find a new life,'' he said. ''It can put you under a lot of stress.''
Long-term injuries and surgeries that take players out of the game and away from close, regular contact with teammates can also be factors in mental health problems. Being forced to stop playing professionally because of injury or because clubs won't offer another contract can be particularly hard to cope with, Gouttebarge noted.
''This has been recognized in other sports as a huge cause of mental health issues,'' he said. ''The guy who is willing to retire or to stop his career is really (in) a different kind of situation to the one who is forced to retire.''
He called the study ''a good first step'' toward identifying the scope of mental health issues in football. The survey is expanding to players in France and from French-speaking nations in Africa, with plans to also study players in Spanish-speaking countries and Japan, Gouttebarge said.
