Africa-born Eder, who was Portugal's hero in the 2016 European Championship final against France, has now revealed that he considered taking his own life two years ago.
The striker, who was not rated by many Portuguese fans at the time, scored his adopted country's winning goal in the Euro 2016 final against the host nation.
The 28-year-old was reportedly mocked by supporters during the 2014 FIFA World Cup in Brazil, with many in media questioning why he was included in the squad for the tournament.
"My mind went to some very bad places. I went through a very low phase," Eder said, as quoted by the Daily Mail.
"I had suffered some bad injuries and went to the World Cup, and things didn't go well.
"It was hard. I struggled to believe in things and dream again. It was a really horrible period for me and you wonder whether you can escape it."
The former Swansea forward also admitted that he went to see a mental specialist named Susana Torres, who helped him get through his tough time.
"I worked hard on my mentality and began to dream again. Susana was the catalyst. She helped a lot," Eder added.
"I think footballers are still a bit funny about this kind of thing. Some think that they can seem weaker. But it's changing."
The striker is yet to get off the mark for his new club Lille, but has played four games and assisted two goals in all competitions so far.
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