Considered one of the greatest strikers of his generation, Ronaldo won two FIFA World Cups with Brazil as well as two Ballon D'ors.
The three-time FIFA World player of the year suffered serious knee injuries during his career that clearly limited his abilities and many have been left to wonder what might have been had his fitness been kinder to him.
In a new documentary on DAZN, Ronaldo discussed mental health in football with former Madrid and Brazil team-mate Roberto Carlos.
"Today I am in therapy," Ronaldo said. "I have been in therapy for two and a half years, and I understand myself much better than before.
"But then again, I'm from a generation in which you were thrown into the arena and you had to do your best without the slightest hint of drama.
"I look back, and I see that yes, we were exposed to a very, very big mental strain and without any preparation for it.
"Also because it was the beginning of the internet era, with the speed at which information travels. At that time, there was no concern about the mental health of the players.
"Today players are much better prepared, they are given the medical attention they need to face the day to day, and players are studied more: the profiles of each player, how they react, how they should react.
"In my time, there was none of that, unfortunately, because we have known all our lives that soccer can cause a lot of stress and be very decisive for the rest of our lives."
He added: "The reality is that we didn't even know this kind of problem existed. It was absolutely ignored among our generation.
"Many, obviously, have gone through terrible times, even depression, because of the lack of privacy, the lack of freedom.
"It is true that the problems were very obvious, but the solutions were not very available."
Ronaldo played for the likes of PSV Eindhoven, Real Madrid, Inter Milan and AC Milan during his career.
He scored 62 goals in 98 appearances for the Brazil national team.
