The research showed that 26% of players reported mental health problems with that figure rising to 39% among retired players. FIFPro's study of 180 players in six countries including Scotland, Netherlands and the Republic of Ireland showed that 7% smoke and 19% reported "adverse alcohol behaviour".
Dr Vincent Gouttebarge, FIFPro's chief medical officer, said: "Contrary to popular belief, the life of a professional footballer has some dark sides.Former professional footballers report more mental health problems than current players, endorsing that the period just after retirement from professional football is a critical one for many players. We found mental illness among former professional footballers occurs more often than in other measured populations."
Last week, Mind Games: Mental Health in Scottish football screened for the first time. The 15-minute film, featuring Neil Lennon, was produced by PFA Scotland in conjunction with Scottish Association for Mental Health. In it the Celtic manager speaks about his battle against depression.
"I remember I was a player at Celtic and we had beaten Rangers 2-0 at Ibrox," he said. "I was in the middle of a dressing-room that was euphoric but I couldn't actually remember anything about the match. All I knew was I wanted to get away from there and go home to a darkened room."
The other countries taking part were the USA, Australia and New Zealand. The former New Zealand captain Chris Jackson, once of Wimbledon, said his disappointment at not making it in European football led to drug and alcohol abuse.
He told FIFPro: "Before international games I would be taking drugs and partying with friends. Then days later I was trying to mark Lothar Matthaus or Ronaldinho. The pressure bottled up for years particularly when I captained different teams and had to be the face of the team when going through tough times. It was coupled with depression as well."